When you get to a stop sign after another car is there already and clearly has the right of way, yet they wait for you to go first. So annoying! It takes way longer than if they would just go first like they're supposed to!
Same thing as a pedestrian, when you're waiting to cross the street in middle of a block (not crosswalk), and one car is coming so you say to yourself "as soon as this car goes by I'll go" but lo and behold, as the car approaches, they begin to slooooooooow down and come to a complete stop right in front of you to be "courteous" to you and let you go... It takes A LOT longer than if the car would just continue driving as it should. Plus, it makes you feel like you are burdening the driver, which you never intended to do...