Definitely agree – it’s something I’ve been doing for a while and, with a line of cars, I reckon (maybe) that thanking the first for giving room seems to positively affect the next. Thank them and it feels like it sometimes carries on…
It’s as easy to wave thanks as it is to gesticulate a grievance. Along teamhurtmore’s “maintaining the balance” theory, I’m of the opinion that (some) people base judgement of a collective on the actions of a few. Jump a red light and the motorist that sees you *may* decide to assume that all cyclists jump lights. Work it the other way and be polite? Might just help, I hope, in my naive little world 🙂