I think I know what you mean about missing something with children. I know what Ron means when he is afraid he's missing something. While sentimentalized, I can see / concede that. A few moments here and there, plus -- my parents actually care about us as people in a way that few other people care about their children -- so I tend to believe them when they say it is a good thing. But, it is THE ONLY THING my parents wanted out of life -- to raise a great family.
When I told Ron we could have one child, after he finally stopped obsessing about having a boy (!), I had in mind some fun, super-successful artist/academic couples who have one child -- more of a "my body can do this, I want to test it out" sort of thing for me. I tend to worry, especially about money and time, and we tend to negotiate away from "normal" differently, and sort of end up both super normal and super skewed, so it would be one hella "journey", but we would either be the very most annoying and controlling child-focused parents on the planet or we would get it right after a lot of heart ache. I, personally, would rather nap in peace, though.