I always try to remember to take earplugs. The amount of hearing loss my dad has just from power tool usage makes me want to keep what's left of mine. I've been to enough concerts without them, anyway.
Gratuitous moshing is what got me to start this thread. I went to see Boris last night (they're a Japanese drone/psychedelic/shoegaze band). Apparently their labelmates in the US are hardcore/death metal/whatever acts, so thanks to the opening acts the show drew a lot of those types, hence the moshpit during Boris' set.
Last time I ran into this, it was at a Les Claypool concert. And I mean, sure, Primus and moshing went hand in hand, but Primus is basically done, and Claypool's current material is about as far as I can imagine from what should incite moshing.
I don't go to Warped tour, hardcore shows, punk shows, metal shows, whatever, because I know what to expect from them. But some people will take any excuse to mosh.