If you haven't seen the episode "The Changing of the Guard" with Donald Pleasance, you must watch it. It's rather atypical for TZ in that it is poignant rather than creepy. It's guaranteed to bring a lump to your throat. I was unable to find the full version of the original episode on YouTube, but you (and everyone here) should keep an eye out for it.
"I haven't been vaccinated" would be another one for sure.