I used to mosh quite a lot. Then the big metalcore craze down South bought in that wave of 'hardcore dancing', and it suddenly wasn't fun anymore. The fucking kids nowadays will karate kick you in the face and then not pick you up. I refuse to mosh at pretty much anywhere that admits under 18s, anywhere where more than five people are wearing a raggedy Palestinian keffiyeh as a bandana, or anywhere where the crowd basically does not seem to understand that a mosh pit is not actually a streetfight with sillier clothes.
Funniest mosh-related thing I ever saw, a pit was forming to a support band, and these two, call 'em 'hardcore' kids, started bouncing off each other, basically. Then they started slamming into folks on the edge of the pit. Dickish. I clearly saw what happened next: one of them shoved the other into the back of an ENORMOUS metalhead, spilling half his pint up his girlfriends back. The metalhead calmly wiped down her jacket, handed her his beer, then turned round and clotheslined both of them. Then the pit really took off.