When a snippet behaves strangely, beginners often want to change it right away. That reaction is understandable, but it usually leads to random edits and weaker confidence.
A better first move is to read the snippet line by line and ask what the current version actually does. Which values exist? Where do they change? What does each line try to do? Which line first stops matching the intended goal?
Tracing matters because even a tiny bug can distort a workflow. A wrong variable name can break a count. A backwards comparison can send rows into the wrong bucket. A missing update can leave the learner trusting a stale value.
Debugging becomes less scary when the learner treats it as explanation before correction.