I'm sure we've talked about this somewhere before. I have synesthesia and love it. I didn't have a clue until one night at band practice I mentioned to my mates I use colour to identify the key we play in at sessions (I play bouzouki and was the sole accompanist).

It seems quite common, and the expression of the condition varies wildly between folk. I also see weeks and years as shapes and colours.

Deja vu as green? It's wonderful!