I have everything logged in my head, account details,ni number,membership number ,card details,birthdays,anniversaries,store account numbers phone numbers (inc mobiles) details of every car I have ever owned and that our families have owned, reg numbers, sizes for everyone shoes/clothes, diary dates for school, pin numbers, past bank account details its endless actually.
I have a photographic memory and can remember a lot of things in minute detail,it annoys the hell out of everyone!! my daughter has inherited this skill and my 7 year old son is a human calculator (seriously!) so its obviously a family trait!!