I remember playing Giants: Citizen Kabuto on a PC that went far above the recommended settings, and at the start the game ran fine and looked good. Towards the end of the game things got much worse, though (might have been a memory leak or something), and it became nearly unplayable with even passable-looking settings. I lowered the settings so that the game looked
terrible, with buildings that looked like they were made from four polygons if you got more than ten feet away from them. It was especially jarring when some other parts of the game were much more detailed so that the shittiness stood out even more. The game was still funny as hell despite the fact that the endgame kind of sucked, but I doubt I would've got very far in it had it looked like that from the start.
GTA3 also ran like shit on that same computer, as its framerate was barely in the two digits. At least it was consistent enough that it was somewhat playable. Before that, Escape From Monkey Island was even worse without a proper GPU, but again playable because adventure game. Rogue Spear suffered from horrible framerate to a point where it became simply unplayable without autoaim or other such faggotry, but I still got halfway through it before giving up. I could list plenty of other games that ran like shit but which I still wanted to play, but those are the first ones that came to mind. Nowadays I probably wouldn't bother with such games, but at one point my endurance level was much higher.
I do think some games look a bit better on lower settings. Higher resolution sometimes makes things look too sharp, sterile and somewhat unnatural whereas a lower resolution gives a bit of warmth to it. This especially applies to many first-person games from around 2000. I also generally dislike high-res patches for isometric games. I'll join the motion blur / bloom / depth of field hate squad as well, save for some exceptions here and there (like Dark Souls that's really meant to be played with DoF enabled). Can't really think of an example where turning
everything to low would make the game look better, though, and you'd probably need to have serious problems or a pretty horrible art direction for that to happen (like
this becoming
this when turning everything from low to high).