It's often easy to tell a mistake. Usually shortly after the fact if it's your own mistake. But often during if you are watching someone else make a mistake.
What's a lot harder is to tell whether that mistake is the first one in a pattern. We often chalk up mistakes to a moment of weakness, naivete, or confusion. But how often have you seen yourself or someone else repeat a mistake over and over?
With every mistake, we should ask whether we've really learned from it? Or will that mistake just be the first in a much larger pattern that we need to break?