Our 25-man raid spent maybe several tries to no avail on an ICC boss one evening and the next time we raided someone mentioned not wanting to go through that again. If you wipe in a heroic its the end of the world.
I remember wiping in instances, one was probably Shadow Labyrinth, so many times our gear broke. But nowadays you better not slip up and wipe or the heroic group disbands or the raid doesn't show up the next night.
I have to admit I like wiping less myself and do sub 15 minute runs. But as far as raid instances are concerned I don't want to one-shot things I've never seen before.
Well let me explain that better. The other night our group wiped, made adjustments, wiped, made more adjustments, wiped, said we were close and going to give it another try, then nailed it. It felt great! Not the level of say a Lich King kill Finnish nerdgasm, but we cheered.
35 minutes ago