Jackart speaks for England here:
The fact is, for most people, the best time of your life is 15-25.
Happiness research corroborates this. On average, happiness does indeed fall after one's teens and early 20s.
One reason for this is that in one's youth one has high expectations, and as these are missed, one becomes melancholic. As J says:
the fact you're not PM, decorated war hero, racing driver, star of stage and screen, or billionaire entrepreneur you set out to be, is a itch at the back of your mind.
But there's good news here. The research also shows that happiness rises after one's mid 40s - in the UK by more than can be explained by rising incomes. This could be because by then we adapt to our position, so our relative failure in life no longer troubles us.
For me, this raises three issues.
One is the status of adaptive preferences. Insofar as 50-somethings have reduced their desires to match their circumstances they might seem happy, but is this really a good thing? Isn't there is instead something sad about contenting oneself with little?
Secondly - and perhaps contradicting the above - doesn't this show the importance to well-being of real freedom? I'm on the upward part of the U curve. A big reason for this is that I'm free. A combination of wealth and modest tastes means I'm mostly freed from desire; I'm freeish from worries about work and presenteeism; free from having people dependent on me; free from giving a toss what others think; and can look forward to even more freedom when I retire in a few years. (It could be that, as Oxford's greatest graduate sang, "freedom's just another word for nothing left to lose.") One reason those younger than me are unhappier is that - as J implies - they have less freedom.
Thirdly, isn't there a class aspect here?
I mean this in two senses. One is that if your health has been broken by hard manual work, one might not enjoy an upward leg in happiness later in life.
Also, I suspect a big difference between J and me is our class backgrounds. J says: "I had enough money from loans, parental indulgence, holiday jobs and the TA to do more or less whatever I wanted." This was not my experience. My youth was instead a mostly joyless and sexless life of work. Chalet girls never threw themselves at me, partly because I couldn't afford skiing holidays.
In this sense, though, I'm lucky. I look back at my youth not with Bridesheadian nostalgia but with relief at having escaped. What's more, coming from a poor background gave me low expectations: whereas J regrets not becoming a billionaire entrepreneur, I rejoice in not having to worry about the leccy bill.
My point here, though, is not about iniquities of class, but merely to note that our satisfaction, or not, with life is something we inherit from our parents. None of us is a self-made person.
Another thing: Jackart is entirely right to say UKIP is a contemptible party of by and for stupid, angry people.