I've been playing more games lately and I don't feel guilty when I'm done (unless I've totally forsaken work I have to do or something), but I do feel differently depending on what game I was playing.
I've been starting to wonder why I play grindy, collecting games like Marvel Heroes (started playing maybe a month ago). It seems like I just play to grind, level up, randomly earn some new item, and eventually earn enough in-game currency to buy another hero and start again. It's not particularly fun once the novelty of trying a new hero wears off.
After playing something like TF2, though, I feel good. There's skill involved in a FPS and it is fun competing (even in a totally casual, silly game like TF2). Grinding for loot and XP has become boring to me, but playing in what is essentially a virtual pickup basketball game is much more engaging and satisfying.