In my view, absolutely not. I've had a few encounters with some retard called AFCNumber01 who keeps slamming at every opportunity, not only me but everyone else he came across. And I must say I found it immensly satisfying shovelling him/her into the gravel at Fuji's 1st corner!!
My worst habit is spending too much time worrying about others people races and not focusing on mine, especially when I'm leading the race. I'm for ever looking over my shoulder so to speak.
If I've not played GT for a while then I need a few races before I stop braking to late and oversteering into a corner.
That might be due to the fact that drinking can help you to relax, I've found it can help at times as well, but I've never tried it when playing GT.