I rarely swear in public.

But a guaranteed way to accelerate my silent, inner voice to audible f-bomb escape velocity is to make me wait at an intersection, giving you the right-of-way, as you surreptitiously slow down, slower, slower, only to turn at the last moment, never recalling what a turn signal is for. At that moment I'm a crusty sailor, breathing scatological invective at you and your birth mother who—while I'm sure is a sweet woman—shares shock at your casual indifference to others.