Noob graphics question

Does graphics programming appreciate good coding practices, like good variable names or refactoring out functionality or short methods?  Or is it so geared towards high performance that all of the good coding practices I've learned doing C# or Java are actually bad?  For trying to learn from other people's code the best approach I've found is refactoring the code until all of the names mean something to me, but when looking on examples at shadertoy.com it seems really common to have magic numbers everywhere, and really large monolithic functions.