Interesting topic! One could write an entire book on that subject
One thing that always makes me proud is finishing a project that I start. Some day, a few (or many) years down the road, I might stumble upon what I made and be embarrassed for a second at the spelling mistakes or grammar issues, and smile fondly remembering days that have gone by. What does success mean to you? That is probably the most important question.
Anyways, whatever you consider success to be, I hope you achieve it!
A teenager's favorite phrase:No sé y no me importa.
Translation: I don't know and I don't care