What’s wrong with being immature?

If you’re an adult and you’re in public, it’s unpleasant and annoying. We live in a society, and libertarians can say “I do what I want” until they’re blue in the face but it’s just inconsiderate of dealing with other people. If you’re in private, act as silly and immature as you want. But don’t burden other people with your lack of discretion and care for other people.