Let’s say you’re a developer — and you probably are if you’re reading this. How do you know if you have a generally sunny, optimistic set of mind or a gloomy, pessimistic attitude? It’s very simple. You know how you constantly look at 6 month old code and see a better way to rewrite the code? An optimist rewrites that code and says “damn, the new code is so much cleaner!” The pessimist rewrites the old code and says “damn, that old code sure was a mess.”
And if you never find any thing wrong with your 6 month old code? You sir are either severely lacking in retrospection and/or you might very well be unconsciously incompetent.