He's sad because he didn't use k6 for stress testing his web application

Web application stress testing with K6

When deploying an application to the web performance can be (and usually is) an important factor. Running it on your dev machine isn’t really a good indicator of how well your application will run, however. Finding out how well your application performs before you deploy is a good idea. One way we can accomplish that is by stress testing your web application using a tool called K6.