It was easier to say hi back when I was driving my E39, as it seemed like I was a fellow BMW driver and not just a car lover. But I am also known to have chased down a few E39 M5's when they first came out, but hey, being over zealous just means I like your car!
It seems as the M5 ages on and the true M lovers are sticking with their wonderful cars that the smiles, headnods, and waves are a little bit better recieved.