As passenger in a recent modern car, I discovered an odd phenomeon. The car doors are spring loaded, such that opening less than a defined angle e.g. 45 deg, the door wants to close. Opening further beyound that angle, the door wants to fully open.
This feature easily results in the car door hitting a car parked next to it. The occupant stepping out doesn't realise that the door will tend to spring open by itself when beyound the critical angle. Presumably this is intended as a "helpful" design feature, but with unitended consequences to say the least...