I thought the answer was fairly simple -- they tell stories (and funny, vaguely incongruous ones, at that). But after watching a few times I saw something extra that really works in them, they leave enough “space” for co-creation.
It seems to me that part of the trick of telling a compelling story is not only getting the content itself right, but also leaving the viewer enough leeway to fill in blanks with personally meaningful or, in this case, funny details. They don’t set out the entire story and tie it up with a bow, but they give enough snippets of dialogue and story that we are drawn in to create the rest of the story. Different remind people events and experiences in their own lives.
So, you have probably seen them, but enjoy anyway!