This comes up once in a while. I grew up in Southeast Alaska, where it rains so much you almost need gills. Most people with a background like that don't seem to care one way or the other about a little wetness; I've never had a trip get "ruined" by rain. I think it boils to personality, what a person wants/expects from a trip, and their gear. I'd prefer showers to perpetually hot weather.

As far as what to do when it rains, I try to read the people I'm with. Some people are obviously unhappy when it happens, and for them it seems worth it to cut the miles short that day so they can sit in the tent. I don't want to force any hiking on people when they won't enjoy it. They might misinterpret my lack of change in behavior when it rains as a way of trying to make things miserable for them.