teshuva

for the most part people are who they are unless they make an effort to change . even then their internal tendencies are still there, its just up to us to decide which direction we channel them.
someone who is very excitable will likely always be this way unless he retrains himself to react differently and even then his first reaction might be to fly off the handle. he could also use his excitability to aid those who need a voice but are too quiet to voice them . they could be a public advocate since they well know how to criticize authority.
a very jappy girl might always want to wear chanel , but know she is not able to afford such luxury so she's merely a gap jap. this desire for the very best is not necessarily a bad thing. one could use this tendency to provide quality clothing for the poor so they will be presentable for job interviews.
i think that the idea of changing one's shortcomings into assets is what it means to do teshuva. one may not be able to change core personality traits, but one is capable of controlling how one uses them.