I think it's rare for someone to reach the age of 40, as I have, and not have regrets about past decisions. I've got more than my fair share, I think, but one of the ones -- a fairly inconsequential one, in the grand scheme, to be sure -- I've been thinking about lately is my periodic obsession with cleaning my gaming "house." This begins every so often when I look at my shelves, see a game, and say, "I'll never play that again." Then, I take the game (and its supplements) off my shelf and sell it, give it away, or, in some extreme cases, throw it into the garbage.
Of course, a few years later, I'll remember these games and wish I hadn't gotten rid of them. It's pretty much guaranteed to happen and yet, until recently, I don't think I really learned my lesson. Now, my garage is filled with plastic boxes of games I haven't played in years and likely won't ever play again, but I'm no longer willing to take that chance. I remember all too well, back in 1987, shortly before I graduated from high school, selling off my entire collection of Traveller books and games, because I'd fallen in love with GDW's Traveller: 2300 (as 2300 A.D.) was called at its release. I simply loved the game, which seemed so much better and more "up to date" than the stodgy old Traveller with its Golden Age SF conventions. I figured I'd never play Traveller again and, since I was going away from home to college soon, I'd need to pare down my RPG collection anyway.
Needless to say, I eventually had to re-acquire those Traveller books and games, often at great expense, and some of them I've still never managed to get a hold of. Traumatic (and embarrassing) though this was, it wasn't the last time I unloaded lots of RPGs I was sure I'd never use again, only to be proven wrong sometime later. Nowadays, I nearly weep for these lost treasures, particularly my old D&D and AD&D products. So, I no longer pitch almost any game I own, even the obviously bad ones. You never can tell when you might want to look at a copy of Greyhawk Adventures again and God help you if you have to pay a second time for stuff like this.