My “best” and “worst” friend in many situations is myself.

Like when I go on a diet!

My worst friend wants the chocolates, and tells me – “Go on, one won’t hurt, it’s only a small piece”.
My worst friend tells me “You don’t need to go to the gym this morning. It’s cold outside, and this bed is so warm and cumfy…”
Fortunately I have learned to listen to my best friend, who does all the things you list in – dealing with it.