the other guys you ride with have road bikes, don't they? riding in a pack of fixies is lots of fun, since everyone's in the same boat, i've found that i watch the other person's legs and cranks a lot more for stopping or slowing cues. i stopped doing critical mass a long time ago because i can't ride my fixie in close proximity to folks who use their brakes often. also they go to slow and i end up getting frustrated with it. also the stupidity and the aggressive attitudes it brings out in motorists AND cyclists alike got to me.