For adults living in normal situations having fun means more than simple physical pleasures or showing off personal skills. For adults fun means doing something productive in some way; it means adding to their accumulation of worthwhile things accomplished. Adolescents are more interested in proving their personal abilities and consider that to be fun, and they are especially fulfilled when they win a game of skill against one of their local competitors.
An adult feels pride in successful accumulation of property and they perceive that accumulation as rewards for their accomplishments, and that success is demonstrated in the size, quality and grandeur of these personal possessions. Total accumulation of money is the universal proof of accomplishment for adults, and those who acquired it through any means are considered to be socially better people by those people at the adult level of social development.
People who live the adult lifestyle try to display their wealth in its best possible way. This is done with bigger, better, cleaner houses, cars, clothes and kids sent to better schools, and all of this done in as high a quality neighborhood as possible. There is a problem with this lifestyle of tending to buy things beyond the money they have available by borrowing from a bank and thus going into debt. That loan can only be obtained by people with good credit because they have a good job, but it does give the impression to others and to the person themselves that they are more successful than they really are. They are putting themselves into a condition of voluntary slavery. I call it slavery because they are compelled to keep working and paying their bills or they will be severely punished by having their possessions taken away from them.
Adults also like to show other people how to do things, and this is commonly seen in their telling other people how things can be done better. The things being taught tend to be common knowledge to people knowledgeable in the field, and are not new ideas, but they are unknown to the person being spoken to. This kind of lecturing is an adult form of fun, and it is very practical for all concerned because everyone profits from the interchange.
When adults are alone and have free time they find it enjoyable to work on projects they consider constructive, such as reading, fishing, gardening, stamp collecting, swimming, golf, walking, or other things typically called hobbies, but which have a worthwhile, cumulative and health-giving quality. They are seeking prestige with themselves and others by living well-ordered lives.
Fun for adults is thought of as work by children.