I honestly can't choose a favorite game of all time, so I'll just pick a good oone.
Baldur's gate had that infuriiating isometric perspective and a multiplayer I could never wrap my head around, plus it's paced like an ant pushing a brick through the desert and level drain is the cheapest tactic this side of mars.
Heroes of Might and Magic 3 brought out conflux and had a really fucking cheaty AI who could spontaneously grow a throng of gnolls a single day, plus units were imbalanced as fuck. Playing inferno was basically just an alternate Hard mode.
Fallout: New Vegas gets a bit boring after you've done the ending once or twice, and the main quest loses a lot of its luster after the first time.
Mass Effect 3 - The ending left me just...disappointed, and it all felt very rushed, with less character interactions and moments than the previous games.
Painkiller could be fucking obtuse about where you were supposed to go or what you were supposed to do, plus the story shit itself inside out big timee.
Deus Ex HR: Doing a non-lethal run is nigh-impossible with what little ammo you get, and stealth just feels a bit buggered up the ass, so combining the two blows chunks. Also, yeah, hacking can get you some neat stuff, but honestly, you could do without it. Also, the boss fights are to be fought only in one way, and that's beefy-headed shooty-shoot mode. Would've liked to see...I dunno, hacking a turret to fight for you or sneaking up on them to some cool effect. Something more than just 'insert 10 more bullets into skull to continue'.
Double Dragon 3: It was hard, almost unfairly so, and most bosses were predictable yet cheap. Horrid combo.
Crash Bandicoot: Hm... 1-3 are almost fucking perfect, I honestly can't think of any criticisms for it.
Tombi: Lots of nonsense logic and fetch quests.
That one wu tang clan fighting game for the Playstation: The computer was a cheating bastard and some of the controls were horridly difficult to input at all, much less in the heat of battle. Seriously, pressing square, triangle and circle at the same time? Not unless my thumb suddenly grew an inch or two in width. Also, imbalanced characters.
Duke Nukem 3D: Quite primitive for an FPS.
Unreal Tournament 2004: Graphics could do with an overhaul, otherwise..hm..
Final Fantasy 8: The story was kinda bananas and the junctioning, while interesting, ultimately didn't really work all that well, plus the graphics are outdated.