Why does everyone love Wilson from Cast Away? Because Tom Hanks' volleyball friend represents tragedy + comedy, a classic 2-for-1. In the first image, Hanks is in danger of drowning, dehydration and death-by-sharks. Yet he further risks his life by leaving his raft to swim after his imaginary friend, sputtering: "Wilson!"
Tragedy + comedy = unforgettable. Hence, Wilson the iconic 2fer.
Readers want 2fer fiction. They want:
(Can you think of others?)
Always give your readers a surface and a below-the-surface. In the words of another Hanks' character:
Writer, reader, runner, teacher, father, infp, huffleclaw.