Playing guitar to us was uncalled for (10)
I believe the answer is:
gratuitous
'uncalled for' is the definition.
(I've seen this before)
'playing guitar to us' is the wordplay.
'playing' indicates anagramming the letters.
'guitar' anagrammed gives 'gratui'.
'gratui'+'to'+'us'='GRATUITOUS'
'was' acts as a link.
(Other definitions for gratuitous that I've seen before include "without justification" , "Done without good reason; free" , "uncalled for" , "Needless" .)