Often the hardest part of a task is just getting started. Once we decide to sit down and work the task or problem goes from large and imposing into simply a step by step challenge to overcome.
So the challenge is not to complete a task, but to sit and start working on it. The challenge is to convince yourself to get started. To remember that the small voice in your head telling you to quickly check social media or to go on YouTube is looking for a momentary hit of pleasure. But in the long run that motivation will bring you nothing but pain.
The way to feel happy and content in the long term is to sit down in the morning and to get to work.