One of the things I love about the Oracle database, and the tools surrounding it, is how well instrumented they are.
For many other programs, when a problem is encountered, sometimes all you can do is Google for occasions where other people have run into a similar problem, see what fixed it for them, try it yourself and just hope for the best.
With Oracle, typically most of the time is spent working out how to enable the relevant instrumentation. Inevitably the next is biggest time-sink is working out how to filter out or aggregate all the information collected, but once this is done the root cause and more often than not, the solution, is obvious.
I admit I’m biased, and of course there are exceptions, but I think this is the reason that most Oracle Database Administrators rely on evidence-based root cause analysis and fixes than blindly following so called “best-practices”.