If I Know what's good for me, why am I sabotaging myself?

If in my brain and body lives only one person, how can I desire great things for myself while also actually sabotaging myself in the way?

Ex: I want to read a book, I know it that's a good thing, but I procrastinate and end up not reading anything while also being fully aware that that's bad?

This is not a question about proscrationation, rather about the different selfs (mind, brain, heart, inner voice, whatever) and how to deal with them.

Scientific material and studies much appreciated.