such as, I am just curious.
the list could go on forever, but I guess i'll give you one example, since you asked.
let's say when you're 16, you start working for a retail store, dealing constantly with customers. you're working for a business, doing business, for money, not grades, which is an entirely different playing field and an entirely different mentality. year after year, you continue dealing with people, selling them things, managing your work time with friends/family/school/other responsibilities, and when you get a little older and more experienced, you start to maybe be in charge of a few younger people working at the retail store. you put together their work schedules, deal with their requests/problems, manage vacation time with business time, etc. etc, all while going to college and getting your degree. By the time you're in your early twenties, you have years of experience dealing with being in a business environment where money is on the line along with having responsibilities to other people.
now, when you're 25, you apply for a sales job at Company X. your first "Real Job". the person who already has years of experience dealing with people in a work environment will transition very smoothly into a job like that, whereas a complete newbie to the world of work will be at a disadvantage. They've never held a job, never had to report to and answer to a boss, maintain a work schedule, or even pay for anything with their own money.
these are two very, very different people.