Sometimes, the smallest thing can stop a habit from being formed.
I started this year wanting to eat breakfast at my dining room table while reading a book, rather than in my living room in front of the TV. It's a simple change. Instead of walking to the left, walk to the right. Problem solved.
Except I slipped. I'm now in front of the TV again. What happened? Well, two things.
The first is that I had to break an old habit first. I've had the habit of sitting in front of the TV to eat for years. It's hard to break that.
The second was more impactful. I had been eating breakfast at the dining room table for over a month, and then stopped. I walked into my dining room yesterday and realized that I had used the space to fix some electronics and I hadn't cleaned up the space. Clutter had taken away my place to eat my meals. It introduced resistance. I cleaned up the mess, and the resistence is gone. I ate breakfast at my dining room table this morning.
Do you have a habit that you're having trouble making stick? Look for sources of resistence, and clear those out.