OK. Go back to my original comment. I did not put the point across properly in my responses.

All 20 year olds think they know everything. Those exact same 20 year olds when they get older and have learnt a lot more and are a lot wiser will realise that they dont know everything, like they thought they did as 20 year olds . Obviously there are exceptions to the rule who will always think they know everything, but I guess I will just put that down to low IQ.