I wonder, how are you "driving"? Are you sitting behind the wheel doing nothing except watch really good everything the car does so you can take over when neede

I wonder, how are you "driving"? Are you sitting behind the wheel doing nothing except watch really good everything the car does so you can take over when needed? Isn't that a stressful experience? Wouldn't it be more comfortable to just do everything yourself so you know nothing weird can happen? Also, if the car does something crazy, how much time do you have to react? I can imagine in some situations you might have too little time to prevent the accident the car is creating.