I always thought people who went out in sweatpants were lazy slobs with stained shirts who smelled. I think there was even a Seinfeld episode about how it meant people had given up on life the day they went out in sweats.
I hate Seinfeld quotes, so I will say that when in University, a lot of really good looking people wore their sweats to class and it seems like clothing companies took notice to this and stared to offer more variety in colors and styles from the traditional elastic bottom pants that used to leave me pantsless in large crowds in elementary school.
So this is what happens when sweatpants become fashionable, the only thing a person can do to look like they have given up is wear pajamas out in public, like this guy. He didn't even bother getting out of his pajamas and freaky banana slippers to hit up this fast food joint and there's something pretty stylish about not caring.