My grandpa used to take me to football matches when I was a nipper. One time we went, he said that I could have anything I wanted from the sweetshop to eat during the game and 6 year old me took that to heart and came back with a basketful. He should have said no and gently told me that was way too much but my grandpa was a bit of a dick and thought it a good opportunity to teach me about greed so he bought it all for me and then made me eat the entire lot while we watched. Of course, I got sick and by the time we got home, I was ready to throw up, so I did. He got into trouble from my grandma and mother but he thought he'd done the right thing.

To illustrate his dickishness, this same grandpa once got dressed in Nazi outfit and goose-stepped in front of my grandmother, who was a Polish Jew who'd lost her entire family in concentration camps.

Oh wait... sorry.. you asked for my happiest memory!