So much this - in the past I was very stubborn when it came to writing tests, I was like "meh, why waste time on writing tests when I can write new functionalit

So much this - in the past I was very stubborn when it came to writing tests, I was like "meh, why waste time on writing tests when I can write new functionalities in that time?". Now, I'm quite the opposite - whenever I add new functionality, I write as much tests as possible - it makes life so much easier in the future. Yes, sometimes it can be irritating when you change one line in your code and you have to fix 10 tests, but the peace of mind when all tests run successfully after each change in code is priceless.