Seriously, this is a valid point. Introverts, please at least try to have more than a single friend. It's hard, I know, I'm one of you. But I've also been someone else's only friend and sometimes you just can't be there when they need you. It doesn't mean they love you any less but each person is the main character of their own story, not yours, and sometimes you can't be the focus of today's chapter. Having more than one person you can lean on will be better for you and better for each of those friends and it'll help you keep friends longer.