[skydhash]

They can't tell you (not everyone is eloquent), but they sure know why. Struggling to put something in word is not the same as not knowing.

[threethirtytwo]

Much of human behavior is evolved so that we don't understand why. For example human morality is an evolved trait, but you wouldn't know it.

Please explain walking to me so that I can explain it to a person who forgot how to walk such that he can walk after the explanation.

[danielmarkbruce]

Nope, they don't.