ARE DEVELOPERS GOOD TESTERS?

This is a common question in software industry that are faced by the testers. Normally everybody think that since the developer has created the code, he would be the best person to test the code. This assumption is absolutely wrong. Developers can never be good testers. A developer will always have a soft corner towards his code. He would never cause a situation to break his code. He would not think in a negative manner. Since he is the constructor. On the other hand, tester is the destructor. He would always try to break the application. Tester would execute negative as well as positive test cases. Tester himself turns to be a user who is going to use the application for the first time. Never compare a tester with a developer.