A finishing touch shows your intentions.

If you make a cake that is coated in a crumble, it can look a bit messy. If you then add a beautiful made frosting flower on top, it reveals that it wasn’t just that you couldn’t make a tidier looking cake, but that it was your intention to produced a cake that looks exactly that way. Below is an example of this. While they both look good, one looks more intentional than the other.

Medovik - Russian Honey Cake Recipe - YouTube
Medovik Cake: 8-Layer Honey Cake ~ Торт "Медовик" - YouTube

This isn’t limited to only cooking. It can be sports equipment, software interfaces, cars, or any other item that you are working on. Doing enough to show your intentions is when things are finished.