Maybe it's because of what society expects from us. If you're 12 you can already do a ton of things on your own but every adult just tells you what you can't do and is looking down on you as if you know nothing at all. At 16 you probably think most things that are restricted to adults you can handle just fine at age 16 and so on. Then when you're like 35 your boss will expect you to always treat every situation professionally eventhough many times you don't feel prepared to do so at all. The older you get the more likely the chance any person you meet at any given moment is younger than you and they will look up to you as if you know better, because you're an adult and more experienced.