Video game pet peeves:
Non-free camera - Sonic Adventure 2 Battle is a major offender. While the camera was pretty good at tracking you. I like the ability to pan, zoom and rotate the camera freely. And the lack of said abilities has killed me a few times.
Non stacking inventory - I can understand the "bag/puzzle" style inventories for RPGs but an ordinary inventory should be able to stack items. Pokemon Mystery dungeon is the only game where this occurs: Yes, I would like to be able to carry 4 oran berries (healing items) without taking 4 slots!
Obscenely cheap attacks - Final bosses do have the right to be a bit cheap but the key word is a bit. Tabuu from Smash Brothers Brawl is a key example. I can deal with a instant kill attack but to blanket the whole screen with not 1 but 3 of those attacks, one after the other? That's a bit much.
"Chain" bosses - 2 bosses one after the other with no time to heal or for that matter, do anything. This does irritate me a bit because both chain bosses are usually extremely tough. Tales of Symphonia had only one instance but it was a triple chain. First Remiel, then Kratos, then Yggdrasil. Granted, you only have to kill Remiel but without a guide, you don't know that Kratos is optional and you are supposed to lose to Yggdrasil. My friend and died about 10+ times vs Remiel and Kratos (we didn't know Kratos was optional so the second all our characters died, we hit reset.)