"Paul's Case: A Study in Temperament" is the story of a peculiar young man whose heightened sensitivity to aesthetics makes him isolate himself socially and psychologically from his real world. Being "a study in temperament", the title of the story implies that Paul's case is unique and that it can hardly be helped, or changed, by any outer influence: Paul seems to have been born this way.
The evidence of this can be found throughout the story: we know that Paul has been raised by his father, that his mother has been dead for a while, and that neither his mother or his father seem to have passed onto Paul the awkward behaviors and paradigms that Paul tends to follow: the necessity for beautiful surroundings, his preference towards artificiality, and the aversion to anything remotely mundane, such as the smell of cooking and the sight of regular people. Like the narrator explains, Paul had
a shuddering repulsion for the flavorless, colorless mass of every-day existence; a morbid desire for cool things and soft lights and fresh flowers.
These extreme sentiments clash dramatically against Paul's reality. A "Sabbath afternoon" society would never stop to smell fresh flowers, nor would it appreciate the softness or delicate nature of unique things. Although Paul's father had tried to intervene and teach Paul some lessons on common sense and responsibility, these lessons never reached Paul's rationale. Nobody in his immediate circle seems to be a role model for Paul; not one that he would change his life for in its entirety, anyways. As a result, there is no choice for Paul than to make his dreams a reality, even if just for one moment.
When Paul finally makes his fantasy come to life, he can only take it so far. When the money runs out and he is found out, he is faced with the choice of going back to his regular life...or not. He chooses the latter choice, and prefers to end his life rather than to continue to live it the way that it is.