Motivation,where it comes from?

Question:

Motivation,where it comes from?

Why some people seem to suffer from a lack of it while others have it in abundance?
It seems that once we have the essentials(food,shelter….)we’r... still not satisfied and we look for acknowledgement,a sense of achievement or something else????.and push ourselves towards ever greater success.

Best Answer - Chosen by Asker: during my business school studies, my professor have said :
motivation comes from fear to loose and fear of not getting.

sorry for my faults, i am french...