Smooth driving is not defensive driving. Smooth driving is a central concept in pro driving schools (like apex, speed and braking control, situational awareness). To be a good driver (eg. both to yourself and others) you should always aspire to never brake or veer too hard unless you have to. The best drivers I have been with in cars at relatively normal highway speeds give an almost 0 G experience unless they want you to or it is necessary. I doubt too many Maybachs or Bugattis on the Autobahn are not driving smooth. That being said sometimes it does not seem smooth but very aggressive as the best F1, Rally or Isle of Man TT, etc. They do not seem smooth to the regular eye on the track at all but they are super smooth or they would not be able to do what they do. And on the street they would absolutely be 0 G if they wanted to be that smooth.