The title 'Captain' is relevant only in the
context of your day to day working life. It is
of no relevance whatsoever elsewhere and in my
view at least should not be used in any other context. As an aside our ex-military colleagues are only 'entitled' to use ranks of Major(or equivilant) and above in retirement from the forces but thankfully precious few of them do so as far as I am aware.
It seems the notion of being a 'Captain' goes
back to the sea where everyone in charge of a
vessel from the tiniest fishing smack up to a great ocean liner would be called Captain - if one
of a tiny number of skippers of the great liners
or supertankers then perhaps justified but when
one goes down the scale ? The black/blue uniforms
covered in braid and scrambled egg on the cap - it
all dates back to the great days of seafaring. We
put up with it to this day in the airline business
but please when you get back into the car on the
way home leave it on the back seat. To insist on
being called Captain when being called up by crewing(yes, people do !) is nothing more than
pretentious - you know you've done the time and
made the effort to reach the LHS - why go on an
ego-trip, its just not that important !