I've previously discussed "the beat" on here. Varying degrees of musicality seems to be a pretty pervasive theme in other comments and similar discussions.

Ooh. Here's one. I seem to have a faculty for formulating highly inappropriate or subversive responses to things. When asked "what's the most inappropriate personalised message to put on an easter egg?" I immediately come up with "lots of tiny swastikas spelling out 'fuck the police'". This is useful for comedic, literary and poetic purposes, and I can generally recognise other people who have the same faculty if I talk to them for a little while or appraise their work in any detail.

Staying on the subject of poetry, I also have an utterly fastidious and unrelenting need for perfect scansion in poetic verse. When I read or listen to the work of a poet or songwriter, I can generally tell if they have that same need. Over 160 years after his death, for example, I can tell that Edgar Allan Poe was driven to distraction by stray metric feet in the same way I am. If he wasn't, his work wouldn't be the way it is.