Therefore, the title text is deliberately vague. It could be interpreted that it is easy to convince people that you have a cannon on your head, that it is easy to make people believe in a self invented headcanons, or both. Since you are choosing your own interpretation of this title text, the joke is that you are creating your own headcanon. While headcanon may often be ignored or dismissed as a personal theory, a headcannon would be far harder to ignore, as it is a physical object which has a notable (and in this case violent) impact on the real world. As fans of the detective later wrote their own stories, canon became a useful term for distinguishing the information that Conan Doyle provided in the stories from that which was inserted by someone else into the Holmes universe.

TIL that I will take any reason, even the flimsiest possible excuse, to link to this video of a fireworks show where the computer was mistakenly programmed to fire all 7000+ fireworks at the exact same time. I say, be the change you want to see in the world. You can’t just wait for shirtless&nbsp