A great software engineer has a healthy balance between perfectionism and pragmatism. Too often engineers want their code to be perfect, while losing sight of the overall goals of the project. A great programmer also learns not to fall in love with their own code, to keep a healthy skepticism until it's been thoroughly tested, making sure it is the right choice for the project at hand. And yes, I believe have the qualities of a great programmer, though working on my need to be perfect is an ongoing battle.

I think one of the main principles of software engineering, and one I try to live by, is to keep things as simple as possible. You're often already dealing with complex algorithms and design concerns, so no need to make things even more difficult with overly complicated, resource-heavy code. Your code should be simple, lean and easy to read. If you start there, the rest will follow.