Troubleshooting is patience with evidence.

Finding the actual cause of something is mostly a matter of staying with the evidence longer than is comfortable. The temptation is always to decide early and act, because acting feels better than looking. Patience here means being willing to keep observing when you already have a theory, and letting what you see overrule what you expected.

Next time something is broken, give yourself a fixed period of observing before changing anything. Write down what you actually see rather than what you conclude. The cause usually appears in the gap between those two.