YKYAEM if...
... When the weather turns bad on a weekend trip you wonder about the weight penalty of carrying the sunglasses you didn't get a chance to use.
... You can't decide whether to clean your car's solar roof (smoother surface = less drag) or not (more dust = less solar gain).
... Two of the first things you check when researching a possible new car to buy is:
(a) How easy it would be to mount a Kammback on the rear hatch,
(b) Whether there is a block heater available for its engine.
... You use terms like: P&G, PNG, EO(ff)C, EO(n)C, DWL, LOG, GLEN, DFCO, BSFC, bump start, etc., while most drivers only know 'drive' and 'stop'.
... You can't get a wheel clamp for illegal parking because of your wheel skirts. Not that I park illegally