5) Errand of Mercy
This classic tussle with the Klingons isn’t high on the list because it shows Kirk off in some great victory or anything, but for the exact opposite reason: it shows Kirk at a moment when he’s willing to accept that sometimes he will make the wrong judgment, and learn from that mistake as he does here by going against the Klingons. Kirk isn’t the perfect hero we often idealize him as, but a man constantly reckoning with his own humanity and failings—and that’s what makes him such a great character in the first place.
