I love programming. I find it to be a fun and enjoyable activity. However, when I have to do something, sometimes its not fun, but then if, later, I do the exact same thing when I want to, its fun again.

I think its the same thing with games - some games I play do feel like work, but I still enjoy them and I think the reason is because I choose to play when I want to. If I were told "you have to play this game now", then I'd probably hate it, but if I can decide for myself, then I enjoy it. Which games I would choose to play in a given moment depends on the mood I'm in.