Motivation

Where does motivation come from? Does it come from emotion? Does it come from a memory? Does it come from visualization? For many of us it may have been all of these things at different times in this journey we call life. Our thoughts hold the key to shaping our world around us.
I have heard many people say do what you are passionate about. That leads to a whole new question, what are you passionate about? Is it something you can do?
That leads to doubt. How can I remove the block of doubt? Will it be visualization, a memory, emotion that will motivate you?
And so it comes full cycle.
If you have a story or example you would like to post please do.