An exasperated fellow guitarist recently exclaimed to me, "Just because Richard Thompson wrote in in F doesn't mean you have to play it in F."

Transposition is indeed a useful skill. After a few years, most people I know tend to memorise the standard chords in most keys. This system occasionally breaks down when trying to accompany someone determined to sing in C#.

I have occasionally responded to requests for chords on these threads (usually where I am the the fortunate position of getting them from the horse's mouth, so to speak, for songs which aren't in most common songbooks).