I hate how about half the time when I direct one of my sims to interact with someone walking by, they run clear across the neighborhood to wherever the walking sim is heading, then stand there until the action cancels. At which point the sim I wanted to speak with calmly exits the map. I think this one is a genuine bug, or at least unintended. But the thing that annoys me the most, and that seems intentional, is when visiting sims in the welcome wagon calmly help themselves to the leftovers in my sims' fridge. Seriously, who does that?
