FSD is a little too wild west. I also lump ACC and LKAS in here, too. Phantom brake and bad directional input exist for those way too often.
It happens rarely enough, and as I mostly drive on the same roads, I know where it happens as well, usually I disconnect the thing before it gets to the problematic place.
So no, it's so much stressful as annoying. But it does remind me that the claims of self-driving is just horse-shit.
I know what (and where) the problematic spots are for the lane-keeping, so I use it in situations where the benefit is large and the risk is manageable.
There are many places where I won't switch it on and just drive myself.
Also 99% vs 1% depends on how you look at it. The main road I drive is about 200km long, in one direction it does not have any problematic spots. In the other it has 2 lets say 10 meter spots. By distance it's 0.01% problematic. It's not like Desert Bus where it tries to get you all the time.