The X-Files (1993)

Mulder believes in almost anything; Scully believes in evidence. The X-Files turned that one disagreement into the engine of a whole series, and the slow shift from professional suspicion to complete trust is still the benchmark for TV partnerships. Scully is never just the doubter waiting to be proved wrong, which keeps their arguments lively across monster-of-the-week cases and the darker conspiracy episodes alike. The run is long and the alien mythology gets tangled in later seasons, so the standalone episodes are a forgiving way in.