The best piece of coding productivity advice I ever received didn't come from a Principal Engineer. It came from a novelist.
Most developers try to push through to the very end of a feature before they log off for the day. They want the satisfaction of a clean stopping point.
But the writer advised the exact opposite:
"Always end your day right in the middle of a sentence you know exactly how to finish. Leave something undone."
In psychology, this is called the Zeigarnik Effect. The human brain hates open loops. When you stop coding right in the middle of a perfectly understood function, your subconscious keeps the engine running.
When you sit down at your desk the next morning, you have absolutely zero friction. You don't stare at a blank IDE. You just instantly type the rest of the function, and your momentum is unlocked for the entire day.
If you finish everything today, you start with a blank page tomorrow. Always leave a puzzle piece missing.