In several books I've read over the years I noticed a re-occurring topic around "Self Identity" 

Basically the lens through which we view ourselves often shapes our behavior and vice versa 

For example, I used to be a chronically late person because I would tell myself "I'm always busy, I don't have time to be on time" But when I started looking at my self as an "on time person. I arrive on time because I value others and my time" then I will begin to overtime enact behaviors that supported that belief. 

I noticed also that when my mind knows I am not working in the capacity I know I can be I start thinking "I don't deserve more" 

But when I am working at capacity it aligns with my self identity of a "hard worker" and income tends to go up and I feel happier. Kinda interesting how our brains work