In short went out for a coffee with a colleague and she suddenly said "I've been going through my accounts and you forgot to pay me back the 63p I paid for your chocolate bar just before Christmas".
I have some vague recollection of her grabbing us both some chocolate at a petrol station and when I offered her the money her waving it away and saying "don't worry about it just now we'll sort it out sometime" (or words to that affect).
AIBU to have forgotten about it and be a bit embarrassed to have been asked for it months down the line?
I did pay it back when she asked by the way - life is too short to war over 63p - in fact I gave her 70p as I was short on change wondering if I should account for the 7p and ask for it back in September!