Simple hack to always feel good about your days and constantly improve your productivity

Have you ever been in a situation when you did a lot in a day but still upset about not finishing "that important" task? Or ever felt frustrated when you can't close a big job for days? If yes, this hack might help you. Please let me know what you think and how you deal with a similar problem.

The "hack" is very simple. All we need to do is to change the frame on how we look at our days. Instead of chasing the completion of a task, we need to "reward" ourselves for putting work towards it. This simple mind shift enables a habit-forming loop for showing up and doing some work, guarantees that you have at least a few "checked boxes" by the end of the day, and, eventually, will significantly change your productivity. As James Clear teaches in "Atomic Habits"— minor improvements compound.
If you want more science about why this works, ask me in the comments. To keep things short, here is the technique I use:

1. Plan your days. Early morning or the night before works best. Open your to-do list and decide what you will do. Assign every to-do item a time when you'll work on it. Write the plan down on a piece of paper or add it to a calendar. The plan will be your trigger in a habit loop. Planning shouldn't take more than a few minutes of your time.
2. Leave "blocked times" and buffers to accommodate for unexpected. This is important, as things rarely go exactly as planned. Allowing some flexibility will reduce stress and help "survive" random distractions.
3. The plan above is your new micro to-do list for today. All the tasks are "work on thing A for X amount of time". You're guaranteed to complete it.
4. Do your best in the dedicated time and give yourself a big checkbox (and occasionally a candy :-) once the period has ended. You just completed a task. Completing a task feels good. That's your reward.
5. Rinse and repeat. Pick your next time-task. Go complete it for the next dopamine hit.

What are we doing here? We are engineering our days for success. Our to-do lists are full of different tasks. Tasks often depend on other people. Sometimes they're too big for a day. Instead of selecting to-do items and hoping we can finish them today, we are framing it in a way where we are guaranteed to make progress towards those items. If that progress will be enough to complete a task, then fantastic, definitely grab yourself a candy too. If not, you did your best with the time you had. As you get better at planning and build a habit of spending/controlling your time as you want, your productivity will rise too. And you'll also start seeing "time-suckers" more clearly. There is no way back from this road.