not climbing, but driving - an anecdote: coming back from beacon rock one sunny afternoon in a most enlightened state of mind, while also sipping a cold frosty one from the elegant skamania market, i got cut off by some jackass pulling out onto 14 in washougal - usually i'm a very aggressive driver, and in an entirely sober state would no doubt have speed up, yelled at the guy, and tried to pass him. instead, i just turned up "kinky reggae" and went back to jam'n. about 30 seconds later, the jackass, now a good 200 yards ahead of me, gets in a near fatal accident. the car in front of him bizarrely decides to cut a u-turn w/o checkign his mirror, and he t-bones it at 50 mph. if i had been sober, i'd have been up there, racing along at 70 or so. as it was, i was able to calmly set my pale ale down while slowly steering my way through the debris cloud, laughing my ass off (not saying my enlightenment makes me a better human being).
this kind of thing is very true in the alpine - the weather looks iffy and scary - i'm stoned, i'll be extra cautious
at the crag - paranoia - double check knot, gear, shoes, helmet, holds, everything. it certainly doesn't improve my climbing technique though! i've probably ended up welding my feet and hands in cracks more frequently while feeling The Fear.