Deadly Towers. With the aid of a walkthrough, I can have fun with it. I can see how most would hate it, though. Being seriously underpowered at the beginning may have a lot to do with it (and so do the cheap pit deaths, the confusing dungeon, the general sense of not knowing what to do, but I digress).
I like Karate Kid for the NES, too. It's a nice little distraction to play for a half hour or so. And there are so many ways to earn extra lives that it kind of cancels out the frustration of getting juggled to death by enemies and sticks and whatnot.
I also like Rival Turf. Not the best beat-em-up out there, but still more interesting than the Final Fight sequels. Somehow. Brawl Brothers was okay, too. Peace Keepers kinda sucked, though.
T&C Surf Design. Man...that game was shit. But it was fun. Even trying to pretend that you knew how the surfing part worked could be fun sometimes. And the cat in the tuxedo is a stone cold pimp. Tied with Karate Kid for best LJN game.

I could go on forever about crap games I like, so I'll stop here.