I definitely like playing for money - but there are conditions.
I like doing it because it becomes a competition then - or at least reminds us that it is one. I think that sometimes gets lost in golf. Games and sports are competitions and I think that is good for us - keeps us sharp. It seems less folks really try to play it like this - but it is kind of the point of playing. The money just makes it matter. I think it can help with learning to play under a little pressure as well.
Having said that, I don't play for much money. We usually do a match play $2 nassau with automatic presses once you get 2 down. I think the most I've ever lost/won is around $6. But we pay up - every time - before leaving the course. Sometimes that means in beer at the clubhouse.
Also, I only do this with honest, score-keeping players. No mulligans, foot wedges, not taking the distance penalty, etc. If you get in it with a half-asser, you just end up watching him the whole time.