Pends though dunnit? I lived with my dad until I was 33. Worked out ok really, most of the time. Had me own space, did what I wanted, dad din’t really bother me about owt. Just two blokes sharing a flat really. Council place in his name so very cheap rent. Suited me fine on a low wage. Allowed me plenty of disposable to travel, buy stuff like bikes etc.
Plus as already said, there’s cultural considerations. Middle Englanders tend to like plenty of space, but many other cultural groups don’t mind being in close proximity to each other. Maybe it’s cos Middle Englanders are quite insecure and need to be on their own more? Selfishness?
Having said that, I now live on my own, and dunno if I want to give that up, certainly not just yet. Probbly cos I’m insecure and selfish really.