I got kicked in the head in GA at a Radiohead show in high school and almost peed on (by a girl, no less...) at a Dave Matthews Band show. But I've also gotten down front for a couple of great shows by Bob Dylan, Ryan Adams, and a few others. It just depends on the crowd.
I have GA's for Philly 2. And of course I want to be right down front, and I'll be in line early, but I'm not going to squash somebody just to get closer. GA is great because of the experience you share with the people around you, but everybody has to be cool, or GA sucks.
Hopefully everybody will use common sense and common courtesy: not cutting in line, not dropkicking the person in front of them to get 4 inches closer to Bono, not drinking enough to puke on their neighbor.
I know the shows will all be great, whether you have nosebleed seats or GA. Everybody's going to have a blast!