1) Ticks. Rug burn. Banging your knee on a table. Terrible, persisting hangovers.

Lot of things.

2) I think this may be stemming from a misuse of vocabulary. Hugging somepony for a long time isn’t a hug anymore. That’s snuggles. And if you were just a foal that wouldn’t be a big deal. But you’re technically older than I am.

I don’t mind hugs. Hugs are how friends greet one another and say goodbye. Among adults, snuggles are for more intimate relationships. And if somepony has a special somepony, you kinda… don’t do that anymore…

I’m sorry, Strawberry. I should have said something sooner, but I didn’t want to hurt your feelings.

3) Genetic something or other. But it’s more complicated than that Punnett Square crud they teach you in junior high. There’s a lot going on, and science isn’t my specialty.