It was the habits part of org-mode that initially interested me. Being able to schedule a task to repeat every "3 to 7 days" that kept timestamps and was all plain text based? It was the gateway features that got me hooked on Emacs.<p>There was an osx/macOS app that did something similar to the habits in org-mode, but I've forgotten the name of it. Was around from the mid 00s and had a colourful grid showing those times you missed the habit, habits on track, etc. I'm writing this in case anyone remembers it, I hate forgetting stuff!