How do I know? No bugs were reported.<p>People take % of code coverage as some insurance and spend time writing stupid tests instead of writing robust code.<p>People also don&#x27;t think that unit tests are constant maintenance burden and a time waster - you change this and that and then you need to spend time entertaining the tests.<p>Again, use your brain, not your fingers - it&#x27;s that easy! Oh, and don&#x27;t program using a dynamic language saving keystrokes, but wasting, even more, writing brainless unit tests!<p>At least in my personal career, most, though, and real issues come from race conditions. But I&#x27;ve been fortunate to catch them quickly by using my brain. And that&#x27;s what we lack today - developers who use their brains, who don&#x27;t spend too much time on emoji reactions in Slack and finding the right GIF.<p>There&#x27;s plenty lots of code monkeys and code gluers today that can&#x27;t even implement a bubble sort without googling it!