thinks, and feels are for his character to feel alone.
Paul represents the aesthetic movement. This means that he has an exaggerated preoccupation with all things beautiful. Aesthetes believe that life should imitate art, instead of art imitating life. He is one to which the appearance of beauty is most important, especially, an appearance of being something that one is not.

.....there was something of the dandy about him, and he wore an opal pin in his neatly knotted black four-in-hand, and a red carnation in his buttonhole.

Paul’s arrogance toward his teachers and his dislike of school are symbolic of the individual who cannot get used to the world around him, simply because he may or may not truly belong to it. The implication that Cather makes is that Paul is somewhat otherworldly. 

Cather places Paul’s job at the Carnegie Hall for a reason:it suits him perfectly. It is a fake palace where fake situations take place; Paul gets to experience the superficiality of it all while being able to play dress up as an usher and believe to be someone of importance.

It was at the theatre and at Carnegie Hall that Paul really lived; the rest was but a sleep and a forgetting. This was Paul's fairy tale, and it had for him all the allurement of a secret love. The moment he inhaled the gassy, painty, dusty odor behind the scenes, he breathed like a prisoner set free, and felt within him the possibility of doing or saying splendid, brilliant, poetic things.

This is why Paul feels that the artificial, being that it never ages, gets ugly, or dies, is more enticing than the natural world. This is another tenet of aestheticism.

Perhaps it was because, in Paul's world, the natural nearly always wore the guise of ugliness, that a certain element of artificiality seemed to him necessary in beauty.

When Paul decides to live his dream at the Waldorf he does it more out of a sense of desperation than of want. He cannot bare the idea of going to a regular job, and living in Cordelia street forever. He has to somewhat escape his reality from its roots. He may have already considered suicide as his ultimate solution. We never quite know as readers.

To give further evidence of Paul’s aesthetic behavior, consider the flowers as one of the most important motifs of the story. The artificial flowers that Paul admires in 5th avenue are, to him, the symbol of the true beauty of such a gift of nature as a flower is.

The flowers that adorn his room represent the desperate need for Paul to entice ALL of his senses to beauty. Finally, when he buries his lapel flower right before she starts to die symbolizes Paul’s own issues as a whole: he must rather be dead than living a life where ugliness may lurk at any given moment.

To some degree, this question is subjective. A reader could conceivably make an argument that Paul is a wonderfully creative, misunderstood, vibrant, and independent person. That reader could then claim that Paul is someone that is heroic, and his actions and attitudes should be emulated. Personally, I would strongly disagree with that reader. In my experience, most readers enjoy discussing Paul as a character, but they dislike him as a person.

Paul is a troubled teen. He has an unrealistic view of the world around him. He simply can't come to terms with reality, so he uses the world of art as some magical fantasyland of escapism. He believes that his peers, teachers, parents, and so on are all narrow-minded people, and that shows readers just how narrow-minded and naive that Paul is. Paul is materialistic.

Perhaps this is driven by the fact that his father won't even buy him clothes that fit, but it seems to me that Paul is the kind of person that has an unhealthy obsession with money and material goods. This is what pushes him to steal money from his employers and use it to have what he believes will be a grand time in New York City. Paul is quite self-centered and doesn't appear to have a care in the world for anybody other than himself. He's also a habitual liar, which further shows how dishonest of a person he is.

One thing that Willa Cather makes clear, from the beginning until the end of the story, is that Paul is different. He is an elemental; he would rather exist in an environment, than be a full part of it. He witnesses life from a distance: At the Carnegie, he looks at the actors and is pleased to be in their environment. At the Cordelia St. gatherings, he observes without interacting. Even when in New York, Paul tends to keep to himself and just absorbs the dynamics of the people in the dining room.

This is because Paul cannot find a true niche in life. He tries to stand out in school by telling amazing stories which he cannot verify later. He dreads life in Cordelia; he also dreads school, and dreads his own home. It is no wonder that he realizes, in part 2, that this sense of complete dissatisfaction as been with him forever:

... he could not remember the time when he had not been dreading something. Even when he was a little boy, it was always there—behind him, or before, or on either side [...] the dark place into which he dared not look, but from which something seemed always to be watching him—and Paul had done things that were not pretty to watch, he knew...

The sense of dread that Paul lives in indicates that he will never be able to find that niche he seems to be looking for. Or is he, really? He knew that his end would come regardless; that he would never go to Cordelia Street again. He would much rather die than go back to a life where he does not belong. This is indicative even more than Paul knew that there was no niche for him in the first place. He seeks, and cannot find, a place to belong.

Paul was fascinated with the theater. It influenced his thinking and personality more than anything else in his dreary world. He was not a good student because he lived in a fantasy world. Therefore school could not have much influence on his mind. Willa Cather specifies that he was not a reader, and therefore he was not influenced by books either. It is highly significant that he worked as an usher at a theater. According to the narrator:

It was at the theater and at Carnegie Hall that Paul really lived; the rest was but a sleep and a forgetting.

At the time the story was written, 1906, there were no moving pictures, only live drama, or the so-called legitimate theatre. Since Paul's time many millions of young men and women have been captivated by the movies, for better or for worse. Paul is an early example of a young person who is inspired by the dream world of the theater to want to escape from the dreary reality of the world he has to live in. Paul is so impressed by the romanticism of the contemporary theater that he actually becomes an actor in his own world. 

...there was something of the dandy about him...

He is always acting. As actors says, he is always "on," meaning that he is always, so to speak, on stage. We have all known young men and young women like that.

In Theodore Dreiser's novel Sister Carrie, published in 1900, John Hurstwood, a much older man than Paul, embezzles money from his employer and flees to Canada and then to New York City with beautiful, young Caroline Meeber. Hurstwood's money runs out, and he eventually ends up committing suicide. It seems likely that Willa Cather was influenced by Dreiser's novel. She knew Dreiser personally.

Cather's tragic story of Paul could be interpreted as a criticism of art in general. She is continually contrasting Paul's dream world with the ugliness of his life in Pittsburgh. Towards the end of the story, when he feels reality closing in on him, he feels sickened.

The gray monotony stretched before him in hopeless, unrelieved years; Sabbath school, Young People's Meeting, the yellow-papered room, the damp dishtowels; it all rush back upon him with a sickening vividness. He had the old feeling that the orchestra had suddenly stopped, the sinking sensation that the play was over.

Paul despises his teachers at school. He is indifferent to their teaching and tries hard to make them aware of his disdain for them in "polite ways." For instance, he wears a "red carnation in his buttonhole" on the day that he attends the hearing of his disciplinary case. Through the carnation, he hopes to send the message that he is not bothered by his suspension from school and that he still is the "every day Paul." He is rude to his teachers and does not attend to his lessons well.

Paul hates common things. He has a "shuddering repulsion for the flavorless, colorless, mass of everyday existence." He likes "cool things and soft lights and fresh flowers." He particularly likes the arts—theater and music. He loves working as an usher at Carnegie Hall: it is here that he really comes to life. He is a “model usher,” for he loves to play host. He is to be seen running up and down his section of the concert hall, talking to visitors, passing on programs, and being the most helpful usher in the entire hall. He also loves to listen to the symphony, not just for its sake, but because it represents genius and a freeing up of the senses.

In spite of his adoration for the arts, he is not interested in a career in any field of art: "He has no desire to become an actor, any more than he has to become a musician." He aspires to live a glamorous life: traveling to big cities, living in big expensive hotels, wearing expensive clothes, and eating exotic food. Yet, he does not want to work hard at achieving this kind of life. When he is not able to reform into a good student at the school, his father withdraws him from his studies and makes him take up formal employment. He does this for a short time before he decides to steal money from his employer to treat himself to the glamorous things in life, if only for a short time.

Paul acts the way he does because he has a sense that he was meant for better things than the meager life available to him on Cordelia Street. The story begins with him facing a disciplinary panel at his school; he is in trouble for being disrespectful, but his drawing master has a different insight -- "I don't really believe that smile of his comes altogether from insolence; there's something sort of haunted about it.... There is something wrong about the fellow." Part of what is "wrong" is that Paul has an imagination that can't easily be controlled, and he longs for the fine life he sees second hand as an usher at Carnegie Hall. He will lie or do anything that will offer him a glimpse of that glamorous life. After one concert, he follows a famous opera singer to her hotel, gazing after her: when the singer entered the hotel "it seemed to Paul that he, too, entered. He seemed to feel himself go after her up the steps, into the warm, lighted building, into an exotic, tropical world of shiny, glistening surfaces and basking ease." This in stark contrast to his own home, and his domineering father, who terrifies him. Paul is suffocated by the middle class life he leads, and becomes desperate to get out, and find for himself the life he believes he is entitled to. That is why he steals the money and runs away -- he decides it is better to live a few days the way he thinks he was meant to, than spend a whole lifetime in fear and misery and self-loathing.

Paul is motivated to emulate the lifestyles of the rich and famous he so much admires. He wants to be somebody in life instead of the nobody he believes himself to be. He dreams of escaping his ordinary, humdrum existence and living the life of a wealthy young man about town. But there's a big problem. Paul is not prepared to take any active steps to make his dreams come true, so he remains trapped in a fantasy world of his own making.

Instead of doing something positive with his life, Paul steals from his employer and heads off to New York, where he briefly lives out his fantasies. But the harsh realities of the everyday world soon make themselves felt, and once the money runs out, the fantasy dies with it. At least while he was living the dream, Paul had something to hang on to. But now that it's gone, he has nothing left and nowhere to turn. The only way he feels that he can escape his predicament is through taking his own life.

Willa Cather's "Paul's Case: A Study is Temperament" focuses on an aspirational teenager from Pittsburgh who wants to live the "high life." In his pursuit of bigger and better things, Paul gets in trouble at school, steals a lot of money, and sets off for New York City to masquerade as a rich socialite. In the end, he throws himself in front a train rather than go back to Pittsburgh with his father, who is on the way to retrieve his errant son.

Motivation in a story can be external, internal, or a combination of both. For Paul, the external motivation is the kind of cosmopolitan lifestyle he wants for himself: money, luxury, and attention from women. At the same time, Paul is internally motivated by his desire for something more. He can’t bear the thought that he is an ordinary teenage boy, destined to become an ordinary adult like his father. Paul wants to be somebody others can admire, and for him, that person is in the world of theatre, living it up. This underscores Paul’s need for acceptance and success, and although these are external sources, his desire to achieve these is innate.

Based on Paul's suicide, one could also argue that he is motivated by an emptiness he feels within himself. Perhaps Paul wants material, worldly success because he believes it will fill the gaping hole in his psyche. This means that Paul is also motivated by the sadness and anger he feels about his past (i.e., his mother's death).

"Paul's Case: A study in Temperament" is, as the title states, an analysis of the sensitivities that are unique to a curious young man whose dissonance with his environment creates the sad reality of his life.

The exact causes of Paul's odd behavior are not meant to be explained with a medical term, or with a social label. This is why the story is labeled as a "study", and not as a "biography". By "study", Cather implies that the process of analysis is ongoing, and never to be finalized with a "diagnosis". It also entails that Paul will also continue to change and expected to get either better, or worse.

Paul's main problem stems froma social disconnect. This disconnect is aggravated by his extreme sensitivity which, itself, is further aggravated by his environment. As a result, Paul seeks in the mechanical, in the plastic, and in the fantastic the aesthetic ideal that he could never reach if he were a typical young man of his age.

The paragraph that gives evidence of this and which explains Paul's condition the best is the following:

Perhaps it was because, in Paul's world, the natural nearly always wore the guise of ugliness, that a certain element of artificiality seemed to him necessary in beauty.

Here is a symbol of the aesthetic mentality which permeates Paul's behavior. Paul's sensitivity (one which is quite heightened) seeks beauty in all its respects. Therefore, since the natural world with which he cannot connect does not provide him what he seeks, his most natural reaction would be to seek it in the artificial palace that is the Carnegie Hall.