Key message: The best motivation is success.
"The following definitions of motivation were gleaned from a variety of psychology textbooks ...
Definition: Motivation is the desire or want to do something.
"Motivation is the driver of cognition, action, and emotion. ... we perform activities because we want to gratify some motive." (Kruglanski, A., Chernikova, M., & Jasko, K. (2016). Aspects of motivation: Reflections on Roy Baumeister’s essay. Motivation & Emotion, 40(1), p. 11)
When we are motivated to do something, there are two possibilities: We do something to achieve a goal or we do something because we like the activity. We speak of motivation when we want to achieve a goal and therefore do an activity that we do not like. But there is also the case when we like activities and there is no particular goal in performing them.
Twice a week I go jogging, but not because I want to achieve a specific goal with it, but because I feel good during and after jogging.
"The execution of the activity becomes its own "goal". ... We do not want a punctual end state here, rather we want to perform the activity as long, frequently and intensively as possible, because the state of performance is highly rewarding in itself." (Rheinberg, F. (2010). Intrinsische Motivation und Flow-Erleben. In J. Heckhausen & H. Heckhausen (Hrsg.), Motivation und Handeln. Berlin: Springer, p. 366, my translation)
The best motivation is success. Therefore, change your behavior in small steps so that you can see success at each step. Then you will be ready to change your attitude.