Focus is choosing one thing. Obsession is when the thing chooses you. Know which one you’re in.

Both of them look identical from outside, since each involves long hours on one subject. The difference is whether you can put it down: focus lets you stop for dinner, sleep, and come back to it in the morning. Obsession keeps running while you are not working, edits your mood, and quietly takes the rest of your life apart to make room for itself.

Test whatever you are deep in by taking one whole day away from it. If stopping is fine, you are focused. If stopping feels impossible, that is worth saying out loud to someone you trust.