It's not even the lines of the bike.
It's the combination of unheard-of reliability and "does everything well" rideability that makes my nether regions tingle.
It's fast as balls, corners like anything, can carry between 2-4 cases of brew and do it all for 600+ miles a day, 2 up.....
......for 200,000+ miles without major work.
You'd be hard pressed to find a bike model that can do so much so well for so long.