Hopefully you never get to peek behind the scenes of much of the world's running infrastructure.

You have to build the thing and test every possible problem before you build it again and do it for real

We all know everyone is perfectly willing to pay and wait for thorough testing so it works perfectly

Nobody would ever underfund something and then complain about how the final product didn't produce 150% of what was promised

Everyone tests in production. Some people also have additional environments to test in.