Innocence and Experience.

It seems that when you're younger, your brain is more flexible and can extend over more things at once; and when you're older, the brain's focus is narrower but you can think more deeply. It really is true that when you're younger, like under 15 years old, it is possible to watch television and read at the same time. Parents have trouble believing it, but in fact that's how it is. I can remember doing my homework in front of the T.V. and being able to take concentrate on both. Kids can have a conversation and listen to music at the same time. Young brains and minds are flexible enough. Then as you get older, you are able to concentrate in more depth, but distractions are harder to cope with. The brain, or mind, is like a camera lens, if I've got it right. The wider the field of focus, the shallower the depth. Narrower focus goes with greater depth.
It makes sense. It fits in with the idea of an Intelligent Designer making the human creature the way he or she is made. When you're young, there is a huge amount to take in and think about. You need to set the mind to 'wide' to take it all in. Without meaning it rudely, a younger mind is more 'easily amused' because everything is new. Then when you get a few years behind you, it's not so simple to find something that keeps your interest - but then you can do more with what you like, because you can think about it more deeply. All that's helpful, because you get the chance to find out what you like and stick more with it. So what all that says is, young minds are 'easily amused' because they're checking out the world, and there's a lot to check. Older people have sorted out what they like and don't like or what interests them and what doesn't. So being 'an old stick in the mud' can really be knowing what you like and what you think. It shows in clothing fashion. You see the different ideas come, and go, and come again; so sooner or later, if you've got a mind of your own, you work out what you like. Trust me - I've been around for a bit. In my life men's ties have gone wide, narrow, wide and narrow again. Women's skirts have gone short, long, short and long again. Back a few years men kept their hair short. Then the 60s happened, and it was long hair on men. Now it's short again, even to the head-shave look. Well, it's a free society! Make your own choice!
It's a pity that over 40s and under 25's don't always realize: if you're over 40,
well, you were under 25 once. In fact, you were much younger than that, obviously. If you're under 25, well guess what: if you live a good long life, you'll be over 40 for at least half of it. So look on the bright side. When you're younger, trying new things can be a real thrill. It's part of getting to know yourself. When you're over 40, or 50 or however long you get, then certain things are settled. You can focus more deeply about the things that you've decided are important or interesting to you.
Like a lot of people, I sometimes think 'if I could have my life over again...' etc. Sure, there are a few mistakes I could avoid, especially things like hurting other peoples' feelings or just being a selfish idiot. But then you learn from your mistakes, as well (or if you don't that really IS being a blockhead).
There was this song in the 70s by Cat Stephens, called "Father and Son". One of the lines goes 'From the moment I could talk I was ordered to listen.' Right! I've had that feeling, too! Everyone on your case wanting to give you the benefit of their experience - or just big-note themselves because they're older. Sometimes you have to do things and find out for yourself. It's important for everyone to remember that. Then again, there are some mistakes that cost too much to make. It can be horrifying when someone finds out the hard way what happens if they drive recklessly.
It's not true that youth is wasted on the young. That is the time when you learn by taking in a lot, and checking out all that there is to see. Older people might sometimes forget that you need your childhood and youth to learn things. Then from the other side it can be really hard to see somebody making what you are sure is a bad mistake. You can't help wanting to stop them.
It's a problem. My personal answer is, I'm glad God is there to keep things under control. The rate of wasted lives would be horrific otherwise.