Finding motivation

Do you ever have those days when you cannot find the motivation to do anything? If I have a day like that it usually starts out with me having a death grip on a cup of coffee while I stare into space wondering, why I am so tired and why do I not want to do anything. What are those things that steal your motivation and what can you do to find it again? Here are a few reasons for a lack of motivation that I think is common and some ideas to solve them.