I quit playing the Benoni. In college I won ALL my Benonis, including the sacrificial win over a 2465-rated master. After college I believe I started LOSING all my Benonis. Kept trotting it out against strong players, hoping to capture lightning again, but instead I just got splattered over and over. Some really awful crushes.
In fact, for a long time in blitz I lost every Benoni WITH EITHER COLOR. Just dreadful results.
So I quit playing it. It had betrayed me :)
I quit playing the Blackmar-Diemer Gambit for completely different reasons. Just wanted to learn to play more classically. You know, learn chess. Good decision.
Recently it seems that 90% of the games I open with 1.d4 are countered with either a QGD or a QID. Seemed like a few years ago the Kings Indian was hot; now it’s almost easier to find a Budapest player than a KID defender. It struck me — there must be a lot of people who’ve tried the King’s Indian and then quit.
What about you — what openings have you cherished and then abandoned? And why?