I found a quote that can be applied both in my personal life and in my life as software tester.
When nothing is sure,
everything is possible.
It applies in my personal life. I do long distance trails. This weekend I took for a walk of 50 km. In august, it will be 100 km.
But it also applies to software development and testing. Sometimes I do not feel confident about the quality of a software version. Suddenly, it gets better and better. It is also possible that it get worse.