Aging

Here's the problem with finding oneself middle-aged yet still feeling youthful and pliant:

As you keep appearing older and older, the feedback you receive from others increasingly conflicts with your inner reality. And the result feels oddly similar to adolescent alienation ("nobody really understands me," etc etc). Which is disturbing, but also, come to think of it, unquestionably youthful!

So, it appears you've got to take some of the bad side of youthfulness along with the good...