Otherwise known as, "John Hancock Figured That If He Was Going To Be Remembered Only For His Signature, He Should Go All Out."
Funnily enough, the formal signing of the Declaration of Independence that he participated in occurred not on July 4th, but a month later. It's also debated over if Hancock actually commented on the size of his name at the time. But the idea of him thumbing his nose at King George the day the United States was born (also not technically on the 4th, because history is fun and messy like that) got stuck in legend, so that's what he's known for. Sure, he served as a governor of Massachusetts and did a few other things, but the only people likely to know that are serious American historians, and maybe artists who did a Wikipedia binge prior to drawing a Friday-night cartoon.
On the plus side, he did get a destroyer ship named after him, which is probably the next best (feasible) thing to excessive pyrotechnics. It will probably surprise no one that his name was written on the stern in a very specific way.
