A friend recommended the short film Whistle and I'll Come to You, which I had actually never even heard of before. It was produced for a BBC television documentary series called Omnibus, and is not a documentary, so don't ask me to explain that, and is instead based on a short story by M.R. James.
Centered on a middle-aged professor vacationing on the English coast, the film is absolutely worth watching for the performance of Michael Hordern as Professor Parkin, as he putters around his room, the coast, and local graveyards, muttering to himself and arguing against the existence of ghosts with a fellow traveler.
It's available to view on YouTube, and embedded below.