for me it's being in a rush, writing code that I would call kluge code, then knowing that there's code in the product that I wish I had written more elegantly.

There's a constant time pressure - the time for refactoring produces no new features - so should I refactor.

I do love programming - I enjoy designing things, inventing new algorithms, figuring out how to generalize and be creative. As stated, the frustration comes from having to rush and not spend the time I would like to spend on a problem.