1. Over the top sex appeal: I get it, men like boobies, but honestly, it's awkward to play or to watch these character models, especially when the camera always focuses on the money shots. Also, most female characters somehow 'sashay' when they walk to show off how curvy their ass is.
2. Zero-choice/customability: Don't get me wrong, many games have been great as totally linear, but I find it so much more fun to be able to do things the way I want to do them. Even Mario gives you the choice of cracking open the boxes for coins or other potential goodies OR to just keep bumbling through the levels.
3. Turn based ANYTHING combined with random encounters: This I find annoying because turn based combat is really slow and random encounters are so frequent. It lengthens gameplay, but not in a fun nor engaging way.
4. Annoying leads: This one is pretty self explanatory. I don't want to play as a douchebag nor as a goodie two shoes. I just want to play a normal human being.
5: Gratingly bad voice acting: OH GOD, WHY?