I am very grateful that my parents brought me up in a decent-size house with a nice biggish backyard. I can't imagine growing up in an apartment. Particularly in today's world where kids don't play in the park unsupervised. It must be even worse for the parents, who can't say "go play outside!" whenever the kids get rowdy and annoying. I don't think indoor living is good for kids.
For people without children apartments are fine of course, which is why I think the ideal city consists of a combination of a higher-density centre with surrounding low density areas.
People need to quit it with the desire to make everyone else live like a single twenty-something professional.