Big 4 not for me, should I be a writer?

I've been interning at a big four for a very long time now. Yes, they must think I'm good or cheap, or both to have extended me for so long. The downside is that I've been with the service group for such a long time that I've seen crazy stuff happen…and I'm thinking to myself "do I really want to come back to this?" I signed my offer letter to intern again next year, however, I don't think I have what it takes to succeed in this service group, or in public accounting. My confidence has taken a hard hit, and there are very few people I can trust in this service group because I've seen people act shady just to get their way. The sad part (well for me) is that some of the staff are fully aware of this, are treated poorly by higher up folks, and they are just counting the days until they can finally leave…I get the sense that certain personalities make it to the top in my service group and I refuse to change my personality and what I stand for just to please certain individuals who could care less about me. So, maybe this service group isn't for me? Maybe big 4 is not for me? Maybe public accounting isn't for me? Maybe I just chose the wrong major? Maybe I'm too nice? I'm starting to think I should just write a book about my experience and hope it sells…but seriously, has anyone's internship made them realize that this profession is a bit too much? Life is too short to be miserable. Sometimes I wish I had not been extended because then I could've been this naive intern who thinks it's a perfect world and everyone loves you and cares about you and wants the best for you…but it's too late now.