What causes generation gap between young people and old people?

The "generation gap" between parents and their children really refers to a lack of, or poor communication. It is worth noting that the generation gap doesn't always apply to all families. There are many families in which coummunication remains consistent and positive.

Most often I think it comes down to the parents and the children having different opinions and values, which by itself is not necessarily a problem. The problem arises when one feels it is necessary to make the other person(s) wrong because of their opinions, beliefs, behavior, etc..

If people can get past this obstacle and refrain from having to be "right" or make the other person "wrong" then communication can remain positive and bring the family closer. The willingness to allow others to have their point of view without making it a contest or a reason for arguing is what will make the biggest difference.