orcishgamer: Hmm, MoO3, I only got it because it was in a bundle, but I feel like I promoted it somehow.
That, I bought it because it was 1$ more to get it with a bundle, but in retrospect, I realized that I'd always have something more worthwhile to play and would probably never go back to that game.
Beyond that:
Earthworm Jim 1 + 2: I just don't like the controls
Blake Stone: Aliens of Gold & Blake Stone: Planet Strike: Got them thinking I'd pick up right where I left off with the shareware version way back when and then, I realized how much shooters have evolved since I played that.
Incoming + Incoming Forces: I really thought I'd like it, but I found it to be empty action.
Personal Nightmare: This game just felt dated. Thought I could handle it and get engrossed in the storyline, but I couldn't get past it's technical limitations.
However, regret is a strong word to describe how I feel about those games.
I wouldn't buy them in hindsight.
That being said: If I hadn't bought them, I wouldn't have realized that I don't like those games.
I consider them experiments that didn't pan out, but that made me discover something.