With the obvious exception of those on this forum, the majority of people with an Alfa today have no idea what they are driving. This is not necessarily a bad thing as without the "normal" people who went out and bought 156s, Alfa might not be here today!
I have to admit, that I rarely acknowledge any Alfa pre-155. As noted by many other posters, it is unusual to get a response from this group anyway - and if you do, it is a huge surprise!
I should also say, that in the 60s and 70s when Alfas really were rare, it was a flash of the headlights (not a wave), that was the standard form of greeting. I have to say, I still think this is a much better (and much more obvious) way to salute a fellow Alfisti.
BTW, don't worry about the lack of response from Mitos, Giuliettas are much worse, most seem to be hire cars!
It's not just me - the only time I have come across another GTV6 on the road, I was driving my 156 SW and although I "flashed", the driver completely ignored me!
On the "real" Alfa debate, some would argue that the disappearance of Milano from the badge marks the end of Alfa - but that would mean the Sud isn't a real Alfa! This one will run and run.