Worst thing I ever experienced with weapon degrading was buying a weapon at the beginning of Baldur's Gate, trying it on a cow and breaking it. Granted, the Iron Crisis and stuff, but come on, it broke after a single swing...

My worst anti-features are:

- Mazes where every wall looks the same and there is no automaping feature. I'm looking at you, Phantasy Star.
- Stealth segments in non-stealth games. Even World of Warcraft has them. And stealth games are my most hated ones.
- Fixed save points. I play those games with a constant fear of the system crashing, a power outage or something.
- Escort missions. Worst idea ever.

Parts of a level that are unreachable without special abilities or equipment that you acquire only in later levels, therefore you need to redo that entire level to get to hitherto closed off areas. I think Metroidvania-style games are actually proud of that feature. I myself hate backtracking and redoing a level all over again after I've completed it.

Good feature : The possibility to customize your character's model.
+
Good feature : The possibility to select your character portrait.
=
Bad feature : The impossibility to match a portrait with a character model.


Drives me crazy on all of these RPG character creation interfaces.

What's worse is when a tutorial flat out hands you all the strategy you need to win. Then you're just running through the motions.
Fine, give me a tutorial on the keyboard commands. Don't tell me "do exactly this and you'll succeed".