Why do so many adults feel like they’re just improvising through life?

From the outside, adulthood looks very structured. Careers, responsibilities, decisions, long-term plans. But when you actually talk to people, a lot of them admit they’re just figuring things out day by day. Some people have good jobs, pay bills, make big life decisions… yet still feel like they’re winging it and hoping it works. I’m curious where this feeling comes from. Is it something about modern life, or has adulthood always been like this?