I broke into PR via an internship. I started out with a boutique fashion PR firm and then I worked my way up, until I started my own company. Eventually, I realized that I love PR as a job skill, but not as my entire job. I think PR is one of those things that is great fun, for a short time. And then it just wears you out.
I also dislike the direction PR is headed: there is increasingly MUCH more emphasis on going out every night and meeting the movers and shakers in the nightlife scene. Less and less business seems to be done during normal hours. And that gets old too.
I also hated how people would automatically brand me as a party-animal networker, simply because I worked in PR. It was like they immediately took me much less seriously.
I think my primary issue with PR is that I worked in the industry in Los Angeles. I really came to HATE dealing with the celebrity machine and all their assorted handlers and drama. It got old really really fast.