Forcing myself to take breaks.
I use the computer a lot and usually take too few breaks. To fix this problem I created a java program running in the background that would block my screen and show a 'Take a break message' aftera specific interval. Later, I rewrote the program and made it quite advanced. I added lots of new features like randombackgrounds, multiple kinds of breaks, reminder sounds, a mode to prevent interrupting games andmore. And all of it is configurable using a JSON file.