A deadline is the friend who shows up at your door and makes you actually finish the thing.

Open-ended work tends to stay open, not because you lack discipline but because nothing is forcing a decision about when it is enough. A date supplies that decision from outside and turns endless improvement into a finished object. It is uncomfortable for exactly the reason it works, since it takes the choice of stopping out of your hands.

If nothing external is pressing on what you are making, invent something. Tell someone you will show them on Thursday, or book the thing that requires it to exist. A commitment to another person works better than a note to yourself.