I have found myself being annoyed lately in a few of my games that gms don't enforce a lot of rules like drawing a weapon takes an action, knowledge checks taking a action. I understand it's not fun to lose an action every round to drawing a weapon or learning some lore, but it cheapens certain feats and class choices. I don't want to be a wet blanket at the table because people are having fun, but it is annoying. I picked an unarmed monk so I never had to draw or stow a weapon. I start every fight giving up an action to activate my stance, but the ranger and fighter are assumed to always have there weapon draw. If questioned they argue why wouldn't they have a weapon drawn, "it's dangerous".

I find the object interact action to be pretty much ignored at a lot of tables. I have also had quite a few people ask what something is and be given a free knowledge roll.

What rules do you see ignored/done wrong that annoy you, but not enough to stop playing.

Edit: I worded this poorly. If it's actually dangerous like a dungeon, or other combat heavy area I expect everyone to be ready for a fight. It's when combat is unexpected. Great example, we were in a dungeon, player a was healing player b when a monster burst into the room. We rolled for combat and played a went first. His first action was to shoot the monster. No one questioned the player, even though he was just healing someone .5 second ago so couldn't have a bow in hand.