I was going to post this as a comment but I decided it deserved it's own thread. I first learned this in my neurophysiology class when my professor gave this illustration to explain neural pathways. Which translated from nerd speak can also mean habits.
Imagine that behind your house there is a large field. Across this field is your job. Normally you'd have to go out of your way to get to work. You decide one day that you're going to walk to work. You walk out your back door and trek through the field. There isn't a path but you keep walking along. It's a tough hike but you make it to work. You do this everyday for a week. The weeds and grass have bent and broken and the path has started to wear down. It's becoming easier. After a month you decide you want to get to work quicker so you decide to bike. It's tough at first because it's bumpy and uneven. Another week goes by and the dirt starts to get harder and the path gets a bit smoother. By the end of the month it's become a very prominent, dirt path. But you want to get work even quicker. So you decide to pave the path so it's smooth and straight. Now you're able to ride you bike as quickly as you'd like. Another couple months go by and you decide biking is too much work. You then widen the path into a road. Now you can easily drive from your backdoor straight to work.
This illustrates a couple different concepts. The shortest distance between two points is straight line. We are hardwired to find the easiest route that takes the least amount of energy. When we start a new habit or change one it's a lot of work because you are building that path from scratch. The more a path is traveled the easier it becomes, the more prominent it becomes, and also more permanent. A road does not easily disappear. This is why it's even harder to change old habits. It's so much quicker and easier to drive down your old road than it is to stick to hiking a new path. The same thing happens with our neural pathways. The more information that is passed from point A to point B the stronger that pathway becomes.
For me, the road out my back door leads straight junk food and binges. Right now I am trekking a confusing, bumpy, hard path towards a healthy relationship with food. The longer I stay on this path and the more work I put into it the easier it will become. And like with all roads, if they aren't kept up eventually they'll start to breakdown. I need to learn to stick to my tiny, frustrating, little hard path and not go back to the old road and fill it's potholes.

