Too Many Late Nights
If you are still staying up late every night partying or even just binge watching Netflix, you probably haven’t fully matured. You know you have to get up early in the morning to go to class or work, so why aren’t you going to bed at a decent time?
Grown ups understand that pajamas are for one thing and one thing only: sleeping. If you are wearing pajamas outside of the house for any other reason than to fetch the mail, for instance to go to the store, you are not a grown up yet.