3D printing is one of the oddly satisfying things a person can do. I love being able to to create a 3D structure that did not exist before, but does after you print it. You, the creator, can either use your design skills to create something new or select from the the thousands of pre designed files, or a little bit of both :) I personally love doing it all.
Here is my view of the 3D printing process. First, you have an idea of something you want to have. It could be as small as a cord anchor or as large as a hydroponic system; whatever you can imagine. when you have your idea, the first thing is to search the internet to see if someone has already created the file(s) you need to create your idea. The amazing thing about 3D printing and creators is people almost always give away designs to others for nothing. Amazing! At this point you can either use you found files or create your own.