People knowing how to use steering wheels. Seriously, when the fuck did this become a complicated thing? I'm not exaggerating when I say two to six times a week I watch people pull out a little, barely turn the wheel -- even when there is nothing behind them! -- drive forwards into the parking space and across three or four spaces and maneuver back into the lane.
The majority of the cars that come in with tire/sidewall damage are to the passenger front/rear tire.
It's like suddenly people don't know how to make a right hand turn without curbing the vehicle.
I've said it before, drivers have lost spacial awareness thanks to onboard cameras.
They can't judge distance anymore and end up hitting the curb when turning/parking.