I can only handle so many questions that are answered within the first 2 pages of the documentation before I lose patience. RTFM evolved as a defence response. But actually, in my experience RTFM-type responses were pretty rare in the channels I frequented and people usually give the benefit of doubt. I usually try to answer and then include a link to where they could have found the information themselves. Sometimes a seemingly lazy question spawns something more interesting.

I haven't used IRC for about a year now but that's not related to user behaviour.