I never kick it when I'm amongst the unwashed masses. I wait for a nice stretch with me and nobody else. Well, I do short shift so I can get those TORs chirping. But I really don't feel the need for speed anymore. I do like to ride "Briskly", but not fast, if that makes any sense.
And part of that is uh, er, well, to be frank, MY FREAKIN AGE.....dammit!
You could also call it maturity and experience. My 10 year stint of OTR saw lots of scary aftermaths of people who exercised bad judgement and combined it with bad driving.