Having kids is unquestioningly one of the best things about my life. I didn't "get it" until the exact moment my first child was born. The moment I saw his face (literally most of his body was still inside of my wife), I broke down into uncontrollable crying and could not stop until it was all over and the nurses were cleaning up.
Watching my kids grow, teaching them, helping them get stronger. The first time my son picked up a book and read to me. Every time my daughter says some word she has no business knowing at 3 (the other day it was, "Daddy are you frustrated?"). It's the best journey of my life and I am so grateful for them and am in such awe of them.
That doesn't mean I'm not jealous of friends who go out at nights. Like most things in life, being a parent means making sacrifices. It's hard work some days but it's the most rewarding thing I've done.
For me, my kids are a thousand times better than having a more expensive car or taking expensive trips. That's a decision you have to make for yourself.
Yup, this is basically my take as well.
I don't really get jealous of the single people around me going out though. At least in my social circles, I would honestly say that I know a lot more depressed single people around me than I do married couples. Either that or the married couples are Oscar award level actors!
I had plenty of fun up until I had a kid in my late 20s, so I guess that factors into it as well.
My wife is also amazing and I could easily go out binge drinking every weekend without issue, but the fact is that I just don't want to 99% of the time.
Watching my son get hype over the newest Pokemon episode or seeing my daughter playing little pretend games she made up herself is 10000x more fulfilling than watching friends sing drunk karaoke or whatever.
Edit: I should also state that I was REALLY lucky and both of our kids are super healthy, never suffered from colic, were sound sleepers from birth, and are generally well-behaved. My daughter has been a bit of a handful recently, but not too bad.
My only real regret is we haven't done as good of a job raising them bilingual as we honestly could have.
My eldest is only 5 though and still picks it up at a good pace, so I am not too worried there.