Introverts also don’t want to socialize every day. Every social interaction drains a little bit of energy, and after a few consecutive days of socializing, we need to shut down. After days of interacting, my brain feels stuffed with other people’s words. They rattle and chatter and knock around and I want to shake them out my ears. That’s when I turn down even invitations I might otherwise accept. When I’ve hit the wall of socializing, no invitation sounds like as much fun as being alone. Our limited ability to socialize causes us to be selective about whom we see when, and how. We are reluctant to squander precious social energy on empty-calorie encounters.