That picture above doesn't show that it was dirty, but it was. There was food splattered on the door and the side of the microwave. And a very little bit on the tray inside. I pulled that out and cleaned it in the sink with soap and water.
I used the same rag with soap and water to wipe the inside of the microwave. And then used a dry towel to shine it up. And it only took a few minutes.
Even a small task done in a few minutes makes me feel better. And then I wonder why we put these tasks off to that mythical later date. Have you completed a small task today?