What happens when you drive off with the gas nozzle still in your car

Before car manufacturers discovered those little plastic straps they use to secure fuel filler caps, it was pretty common to see people driving around with a gas cap on their trunk, not to mention seeing them lying around on the road. Considering how forgetful we humans can be, it is surprising we don’t see more videos like the one below. I can’t say that I would want to stick around there with flames coming out of the pump as they are!