Re: Red flags
Humans are social creatures and for someone to have no friends usually implies that they’re so obnoxious, dramatic, etc that they can’t maintain those type of relationships. I’ve met plenty of people that were introverts but I’ve also met 1-2 people that had zero friends and I quickly found out why.
Also like the other person said, people like that are overly demanding and needy because they don’t have other people to interact with. I dunno…it’s a red flag for me, at least.