Your brain physically shrinks from social isolation and your life is shortened.
There's a theory that there's no such thing as introverts and extroverts, it's just that attractive, charismatic and likeable people get positive reinforcement for socialising and the unattractive, uninteresting, unlikeable people get negative, and that shapes your personality growing up. It's probably an exaggeration but there's probably some truth to it.
Normies don't want to talk to me and even if they for some reason they do, they don't care about what I'm interested in at all and quickly bail from the conversation. It is difficult for me to come up with normie-appropriate responses, like pulling something heavy up from under deep, dirty water.