In order for that to happen, you would need perfect practices, perfect requirements, perfect testing and perfect ‘change control’, and an inhuman ability to nev

In order for that to happen, you would need perfect practices, perfect requirements, perfect testing and perfect ‘change control’, and an inhuman ability to never make a human mistake in the understanding of any one of those things within your team of equally perfect people, so add perfect communication on to the list. Anything less than perfection at any stage will be a vector for bugs, whether that bug is a syntax error, unexpected behavior, or a fully tested and functional feature that doesn’t meet expectation. Mistakes are inevitable and not necessarily bad when you handle them well (move fast and break things says nothing about what you do with all the breakage, so feels immature). Calling them bugs doesn’t change that.