A question like this is actually very broad, as coding encompasses all sorts of different things!
Building a polished design is like crafting a beautiful painting. It reminds me of all of the different UI's I have interacted with throughout my life, from video games to websites, that really resonated with me. There is something so satisfying about using a pretty website that only people growing up surrounded by computers would understand.
Coding a functional back end feels like solving an algebraic math question, balancing different variables and equations, or like a libraian searching through shelves to find the documentation that will help me make my code work properly.
Bringing them both together is the most magical of all. It's where you can finally say you've created something complete. Your first version will never be perfect; if it is, you've launched too late! When you are in this stage it is important to not stop. Don't get side tracked with other things. You have to stay focused and ship something! You're a creator! Not a drafter!
You push your finished product. Hooray! Now you've built something nice and polished and useable! It's all yours and no one can take that from you. You made it, nobody else in the history of the world, past or present, can say the same.
Breathe a sigh of relief and accomplishment. You did it!