What causes the generation gap.

What causes the generation gap. From what I can see it is the saying of grotesque falsehoods. This is usually done to advance some cause of the adults or protect their self image. Or to advance some cause.
This is sometimes on a large scale. A whole generation teaches lies to the young.  The results will be that the young will rebel once they find out they have been lied to. 

There are two aspects to this:
(1) If you are telling and teaching a certain religious tradition then to do so accurately. Do your homework.

(2) Don't lie to protect that tradition. If there are problems with it then don't hide them or make excuses.