They're amazing. They're a lot of work, and a lot of that work is at odd hours ("3am: dad I'm scared of the wind also I accidentally peed on the floor") and/or highly frustrating ("me: son, please stop leaning out that window. son, balancing precariously halfway out his playhouse window: why. me: because if you fall out of it, it will hurt. 2 mins later: falls out of window and it hurts.") (also - feeding kids of any age).
But it's so worth it. My oldest is old enough to be playing with legos, and teaching him how to follow the instructions, and then seeing him both follow the instructions and then also deviate from them sometimes with his own creativity without compromising the rest of the build (well, usually) is just amazing to see happen. And then take this sentiment ^ and apply it to practically every facet of life. Having kids is about finding magic and bonding in both everyday things, like watering the garden together, and in the once-in-a-lifetime things like going on a vacation to someplace.
But of course it's not for everyone! It is really hard work and it takes a certain maturity and disposition for selflessness to be good at it. So I of course respect people who want to opt-out.
But - setting magic aside - so much of our economy is literally predicated on populations either continuously growing or at the very least not shrinking that we need to be careful about fertility rates. I think we can look to Japan to see what happens when you make your society too much of an economic rat race: people either solely focus on it or drop out of it, and both will cause fertility rates to drop.
A good step in the right direction here is that it's probably in the interest of us all that people who want to have kids are enabled to do so. (And indeed we have some policies like this already - public schools, child tax credits, etc).
And note that my concern about none of my coworkers having kids is mostly in this vein ^: it seems to me like it's a bad sign if a bunch of people with ample means are all still deciding not to have kids despite nominally having the funding to bankroll it.