At least you didn't pump a gasoline engine's fuel tank full of diesel (or vice versa).. Or add coolant to your oil... ;^>)
Besides, look at it this way; every mechanical foul-up is an opportunity to stay home, eat well, drink a beer, and smoke a joint.... until you pick a path and your job is done... With the right beer and joint, that might be days of rest and relaxation to be had. ;^>)
getting ready for work one morning, realized Sportster was low on gas. grabbed one of my dads gas jugs & started pouring. too late! it was used motor oil... so i did exactly what you said & took full advantage of bad situation. at least i didn't try to start it & suck oil into the carb & cylinders.