Lottery, as a form of innocent betting, can really provide a lot of fun for a small price. I would be bored to death to watch a soccer game, but when I bet 1€ on it, it suddenly becomes 2 hours of fun. And I don't expect to "win the ticket", cause I already got more than I paid for.

Looking at everything from the profit/cost point of view can lead to a very boring life, for most of the people.