I'm the shit is a popular modern phrase, and it is also the name of a Kanye West song that is incredibly popular. When you say I'm the shit you may think you are being confident but you are actually being arrogant and cocky, neither of which are attractive traits in a person. A search of I'm the shit quotes will show just why this phrase is a poor choice of words. If you want people to like or admire you than humility is a much better trait to develop. When you say I'm the shit it simply shows that you suffer from low self esteem and have a need to feel superior, and instead of attracting people this will actually push them away instead.