No, but apparently it is. Personally, I'm not a big fan of formal anyway - I've only worn a suit ONCE in my entire life, but that was because I was attending a formal party anyway (not quite prom), other than that, just about the "dressiest" I ever get is a particularly nicely designed polo (or sweater if it's winter)... then again, I wear polos all the time anyway. I confess I'm something of a metrosexual, but not to the point that obsess over my personal appearance or anything, but rather I at least put effort into dressing myself for the day, rather than just throw something on that isn't dirty... or even just walk out still in my jammies, like a lot of people do today.
It does seem like most of contemporary society is a lot more open-minded about clothing these days: apparently, walking around in jammies in public is socially acceptable, whereas I can remember a time where wearing sweatpants meant you were a "loser". I always wear sweatpants though, but over the years, my mom had me switch from cuffed pant-legs to open-bottom hems, so I would look "more presentable". I hate jeans, they're terribly uncomfortable. So are khakis.