Sounds like a mason working on a sculpture. You need to identify and cut off all the superfluous parts.

Abstraction is generalization of special cases. If you only consider one case, you can't generalize from it. Only when you get two, can you work out the differences and the similarities. It's like forming the intersection of two sets: You remove all the elements that are not part of both.

I wonder how accurate this process is. If you're not careful, you might confuse experience with being narrow-minded. Thinking outside the box requires you to consider exactly what you know you don't know.