You judged the new kid in September. By March, he was your best friend. Hold the verdict.

First impressions are formed with almost no information and then defended as though they were conclusions. What you observed was a person in an unfamiliar situation, which is close to the least representative version of anyone. The judgment feels like perception and is mostly guesswork that arrived quickly.

Keep the verdict provisional for longer than feels natural. Give someone three or four separate occasions before you decide who they are, especially if the first was awkward. And when you notice you have already decided about someone, go and find one piece of evidence that does not fit. There usually is one.