1 min lesson
When debugging starts with a guess
Work through this case: "The result sounds convincing. Which warning sign do you check first?" Say what you would do and why.
Step 1 of 3
The result may sound finished while this is still true: Editing based on guesses before reproducing.
Interactive diagram. Tab through its regions; each focused region shows its detail in the panel below.
diagram: compare
Pick a row to see what to look for.