Let's think about motivation.
I think motivation is useless. Generally, there is no one source of mental energy that lasts throughout our endeavors. Of course, emotional events produce some motivation but these are rare and only momentary. For example, you may watch a uniquely moving movie and be motivated to produce (study, work, work out, et cetera), but sooner or later, the movie will not motivate you anymore. This is inevitable. Therefore, I argue that, given the scarcity of time, using time to look for a rare and momentary motivation is irrational.
Instead, using that time to learn to produce without motivation makes more sense. And learning to produce without motivation entails two lessons: one, movement is inertial; and two, the objective is to acquire the ability to create an "accident."
First, we need to internalize the concept that movement is inertial. People tend to have this notion that great motivation renders great production, but this is nonsense. Motivation temporarily renders some production, if at all. What is sensible is the notion that great production renders more great production. For example, it is easier to go directly from reading to writing than to have a break for playing in between them. Here is a more elaborate example. Consider which sequence is easier to complete: (1) study for a test - take the test - do homework; or (2) study for a test - take the test - watch television - do homework. The answer is (1), and this is because there is a domino effect. We feel that extending production without a pause is relatively easier than restarting production from a pause. This teaches us that we should try to avoid pauses between productions and keep productions in a series.
Next, we need to learn how to create what I call an "accident," the initial spark to start a chain production. An accident, in this purpose, is a string of small behaviors that triggers a small production in harmony. For example, in order to start writing a research paper, I may execute the strings [use restroom, wash hands, apply hand lotion], then [get coffee, open a book, read some] and then [power computer, play favorite music, run textedit]. When practiced, this method proves to be easier to complete than executing each behavior one by one or executing only the first and the last behaviors. Creating an accident, as you can see, is an intentional grouping of behaviors such that each string increases the momentum toward the next string. Executing behaviors in this manner generates a potential for a chain production and eliminates the need for a motivation.
I leave you the references in the form of imperatives. I hope you never waste time again on looking for a motivation.
Think domino theory, positive feedback loop, and self-fulfilling prophecy. And think Pavlov.