Debuggers are next to useless when dealing with today's distributed systems, all operating asynchronously in parallel. For the kind of bugs (race conditions, co

Debuggers are next to useless when dealing with today's distributed systems, all operating asynchronously in parallel. For the kind of bugs (race conditions, corner cases) that aren't easily caught by compilers, linters, unit tests or code review (in other words, the "Heisenbugs" that can stop a release in its tracks), aggressive logging is the only tool I've ever seen that is useful in-the-wild. I would put forward that proficiency with this style of debugging (closely related to useful performance profiling) is a major factor separating mediocre programmers from the quasi-mythical 10X rockstars.