I certainly have a mental box for “I don’t really want this any more, but that’s because of the way I specifically feel about it rather than because I think it’s a bad game in some absolute sense”. (I feel a lot happier about selling games if I think of them that way!)
Alien Frontiers – liked it enough to go all-in on the 5e Kickstarter, but the Thing It Gets Wrong (your turn requires a fair bit of thought, but you can’t really start doing that until you see the game state at the end of the previous player’s turn) irked me more and more.
Among the Stars – I mean, it’s fine and I’ve had good times with it. But I just look at it on the shelf and think “I’d rather play…”.
The Awful Green Things From Outer Space – it’s still fun but game design has moved on and I can get the same degree of fun with a lot less faff.
Black Orchestra – I’m OK with the theme which I know puts a lot of people off, but after a few plays it feels very much as though the game is won or lost in the item setup and the event deck shuffling, and the bit with humans involved is just working out the predestined course. (I continue to enjoy the other game of Philip duBarry’s that I’ve played, Revolution!.)
Burgle Bros – probably the game I felt most positive about out of this lot, but somehow it palled on me; I’m not sure whether that was because each game felt about the same or because of the randomness. (The more a game is affected by randomness, the shorter I want it to be.)
Colony – this is an example of both. I didn’t think much of it on first play; then I played it a bit more and enjoyed it enough to buy a copy; then I burned out on it, because I started to feel there wasn’t enough mitigation of the dice luck.
Dead of Winter – I know I’ve played it more than the one time I logged on BGG, but I think this was more a gradual decline in enthusiasm. I loved the idea of a Crossroads card that would affect a specific character… but somehow that never actually seemed to happen.
Pandemic – nothing wrong with it as such but Flash Point gave me more of the stuff I liked and less of the stuff I didn’t.
Quantum – I regret getting rid of this just a little, but I found I was never enthused to pull it off the shelf.
Secret Hitler – some interesting ideas but I just like The Resistance better.
Suburbia – my main error was buying the 5★ expansion which nobody should ever play with because it dilutes the game too much. But while I still mildly enjoy it the bookkeeping is a faff and some of my friends are AP-prone in a way that can seriously hang up a game.
Tales of the Arabian Nights – it turns out there are only so many times I want to spend several hours being a cork on the seas of fate.
Zombies!!! – it is what it is, and while I’d rather play this than Zombicide the random layout just lost its appeal.