It's also an amazing way of duck-debugging. By the time you write down what the problem is, you'll figure out where's the issue or at least what you should try next.

"X is giving me an error, I checked X's logs. X communicates with Y... Oh, I need to check Y next!"

And if you can't figure it out, you have the problem and everything you tried documented so you can ask for help and get answers effectively.