Wilf's lecture on civility indeed brings culture and a 'proper English perspective' to the question on returning a 'thumbs up' gesture from the adoring masses of motoring civilians. However....from my point of view...
If it's another guy....a simple wave of the hand....nothing too faggish...just throw up your right hand to indicate you're not carrying a weapon will put your fellow man at ease.
If it's an older lady...a simple nod will do....see Wilf's proper Englishman's nod. Very appropriate, also, to tip the bowler ever so slightly. Try not to drool too noticeably.
If it's a babe....depending on her attire.... motion her to pull over and hop in...or hop 'on' as the case may be. Give her the ride of her life...drooling is acceptable, but try not to drool directly on her....unless, of course, she asks....then, by all means, it's acceptable to drool, but do try to establish a price before things get out of hand...so to speak.
If it's a constable....a proper salute is appropriate. Extend the fingers of the right hand, and bring the tip of your middle finger to touch the right eyebrow and then smartly drop your hand back to the shift knob. Select second gear and throw him/her some 'pipes' as you accelerate away from the officer while maintaining all due respect to the legal speed limit...or not, as the case may warrant.
If it's a fellow Gashole....simply raise up off one cheek and bellow a friendly greeting from your posterior region... returning a proper Gasholian greeting is oh so appropriate in these awkward situations. Meeting a fellow Gashole is indeed a priviledge and an excellent opportunity to 'make one count'....
If it's a fellow Gashole and it happens to be LNP.....just duck down in the car a low as you can go and still see out...then nail the throttle and get outta there as soon as possible, lest you be overcome by the spreading gaseous clouds. Check your mirror frequently to insure you're not being followed...make sure you stay up wind. Do not stop....
