Just about everything humans do (subconsiously) has a purpose. Why wouldn't dreams have a purpose?

My theory it dreams are like an exercise for your braincells. The more you use braincells the thicker the connection parts get and the more banched they get, this is like how you learn stuff.

If you havn't ping ponged in 50 years It's kind of hard again. Becouse the nerve cells that don't get used alot kind of degenerate and get a bit less good in transferring singals.

So, basicly, dreams exercise your braincells.

So, what is your theory on why humans dream.