I ALWAYS try to get standing/GA tickets for a concert, because, for me, that's just part of the live experience at a rock show. Sometimes it happens that I don't manage to get GA tickets, then I take seats and tell myself it's better than not having any tickets at all, but I don't enjoy it as much.
If I want to get to the front I go there early enough. At many venues they close the front section(s) after a certain time when there are enough people in there, so those who are early get the chance to get into the front sections and others don't, I think that's okay.
What I HATE is people pushing their way to the front, usually it's guys who are twice my size who kind of bully their way through to the front rows, God I hate that.
What I consider one of the biggest "evils" in concerts today is people taking photos and making videos with their cell phones. I remember a time when this wasn't possible (good old days), and I honestly feel it takes away so much from the concert experience because a. especially in the front people are holding up their fucking cameras and barring your view and b. people forget to cheer and celebrate because they are so busy taking these damned photos and videos. Crowds aren't the same anymore because of cell phones, I honestly tell you, it's so annoying.