When actors get pigeonholed, that's their own doing to a large degree. Because if you do something that people like, obviously they're going to ask you to do it again. It's up to you to say no. If you're that insecure about working, you'll probably do what you're known to do.
With any group of people in life, sad things happen, and crazy things, and happy things. When you're in the public eye, it's just amplified, that's all.