I think it is very important to teach children to "enjoy life".
I have discovered that I need to explain that advice. One father asked if that would spoil his children. The answer is no, that isn't at all how you enjoy life.
Alas, I am not sure I can explain what I do mean. But I will try.
First, you don't enjoy life by having things. Yes, there is a happiness you get from having something -- good food, nice car, winning a contest, etc. But it is an illusory happiness. When you get a burst of it, it just becomes a little harder to get the next burst, or the next burst isn't as large. Everything then evens out, so the amount of happiness you get from having things stays about the same.
So, how do you enjoy life?
1. You find the find or do interesting things in life. My daughter was recently in a spelling contest, won a second place award, received a certificate for that, and they misspelled her name. My daughter enjoyed the irony.
So, you enjoy life when you wrest the most out of your experiences. You find the humor. You find the interest. You find the learning experience.
Story. My daughter was playing a computer game, and she scored her best score ever, 2857 points. She just missed "Qualifying for the Olympic Team", which required 3001 points. She was frustrated. I thought, and I told her, "There is something wrong when you get your best score ever and you aren't happy." It is natural to strive, and natural to suffer regret when you just miss something you want. But there is also a time to stop and smell the rose of competition, which is to say, stop and enjoy what you have accomplished. Now I think she knows to do this.
2. You find peace with yourself. You behave in such a way that you like yourself.
3. Humans also find enjoyment from a variety of things that are interesting. The obvious one is learning. My friend Marvin regularly seems to choose new things to learn about. Last year it was physics. This year he is trying to learn the psychology of humor.
Or, there is an enjoyment in collecting things.
I think you partially teach this by example.