Freecell has got to be up there. That ubiquitous Windows variant on solitaire, originally included, or so it is alleged, to teach mouse skills, has lived on through many generations. Of course workplaces have mostly wised up and excluded it from work computers, but most people can still waste time on it at home. The trick is that while winning is nearly always possible, it can sometime be rather difficult. Still more insidious, but known to hard core addicts, is the fact that some games are in fact impossible.
The original deal, consists of 32,000 odd (OK, 2^15) deals out of which only one is strictly impossible. It's always out there, looming in the mist, for the hard core addict, ready to sieze the unwary. Thus, even if you are a self-imagined Freecell hotshot who has won 1477 straight games, many with ridiculous ease, you can't get too comfortable.
I personally always get a little nervous when a game numbered 11,*** comes up.