No reason. I've never really eaten biscuits, even as a kid.
Tea...I think it's the years of being on tea duty that put me off. My uncle used to play games with me (board games, cards etc) and the loser had to make tea on demand. It never occurred to me that him being so much older that he was almost guaranteed to win..
He's only 13 years older than me. On the plus side he taught me how to play chess, all card games, pool, darts....and how to chalk the dart board. The latter became a bit of a bane because he'd make me chalk while him and his mates played.