Depends on the game. If it looks like something that wouldn't pass as acceptable in the '90s, it's bad -- if the graphics are so mediocre or horrible that they make the game thoroughly unenjoyable to play, then the game's bad. If they're just ordinary standard, or a bit subpar, but the gameplay is so much fun that you don't pay attention, it doesn't matter. Likewise, if it's eye candy but miserable to play or the dialogue/plot/etc. makes me die inside, it's a terrible game, but I'll stare at the box art. XD But if I'm going to strain my eyes unforgivably to play a game, can it at least not set my retinas on fire?
A personal thing that ticks me off is something like, say, Final Fantasy X -- so very detailed and pixelled that it gets too busy and hurts my eyes. From a distance, the game's gorgeous, but up close and personal, well, I'm not too fond of it. I actually really like 2D and cel-shaded. I don't like it when the graphics are so 'beautiful' they take over the game. Also, I HATE it when in some games, the walls are made of paper practically and the character keeps sticking their hand through it. ><;