In this scene, Portia is unhappy about her predicament. Nerissa adds that people with too much can suffer as much as people with too little; the best way to be happy is to have just enough. She suggests that Portia might apply this principle to her life. Portia replies that this is easier said than done. It would seem that Portia is a rich heiress unnecessarily whining about being unhappy. One with so much wealth could/should have the ability to choose a different way of life. In other words, Portia, having so much wealth, should be able to change the circumstances of her life in order to be happy. However, her lamenting is justified since she has no choice in her future. She is stuck in the position of being waiting to be chosen - from a list of suitors she does not like.
The prince from Naples only talks about horses. Count Palatine is solemn to the point of being nihilistic (not caring about anything). The French lord tries to hard to impress. Falconbridge doesn't speak Portia's language and his personality is "everywhere." The Scottish lord has no backbone (self esteem). The Young German is a drunk. It would seem that Portia is being picky but her complaints of each suitor are justified. More to the point, she is being "picky" because she doesn't not have the power to "pick" her mate herself.
This scene establishes Portia as one who truly desires freedom and independence. She resents her father's will and wants the right to choose her husband. She resents anything or anyone who might tell her what to do. And this desire reflects her personality as one who is independent, an individual. (We will see her utilize her independence and autonomy later in the play.) When the prince of Morocco arrives, Portia continues with her complaints and ethnic stereotypes about any potential suitor. This might reflect a haughty disposition on her part but it shows her consistent desire to be the chooser rather than the one to be chosen.