College sweatshirts are 'casual' instead of dress up. Your parents charge rent. The four food groups are no longer soda, pizza, chips, and cereal. You make thousands of dollars a year - and still can't afford that dream Porsche. Naps are no longer available between noon and 6 p.m.
Sneakers are now 'weekend shoes'.
The weak single you hit in the intramural softball game is now remembered as a Varsity dinger for the League Championship. You get your news from sources other than ESPN Sportscenter and MTV News. You find yourself reminiscing fondly of 2-hour Calculus exams. You actually eat breakfast foods at breakfast time. Grocery lists actually contain relatively healthy food.