After scouting out the edges of the car's handling envelope, and satisfied that the car was benign enough not to kill me below 9/10ths, I turned the nannies off for the day. An hour later, it was raining cats and dogs. Overtaking a semi at less than half-throttle, at rpms below the threshold where the "wild cams" take over, I suddenly found myself with a half turn of 'oppo' pointing the wrong way. Can't quite recall which way that was, but with a semi on one side and a concrete wall on the other and a 2 meter wide car travelling diagonally down a 2.2 meter wide lane... I suppose you could say either way would be wrong!

With the aids back on, the car would still skip briefly over puddles, but wouldn't pitch out sideways any more.
On the really powerful and twitchy cars, aids are definitely necessary, though, and if a car comes with aids in real life, I may or may not use them in the game. Or I may simply use a car that I can drive at the absolute limit without them.