My New Gas Cap

I was trying to do too much in a short period of time. I spaced out while buying gas, and drove off with the gas door open. I noticed it down the street when a thump attracted my attention and I saw the open gas door -- the thump was obviously the cap falling off the roof.
I retraced my route several times until it got too dark; no one had turned it into the gas station. They told me to go to Checker Auto Parts, something I have never done, until today that is.
I located the nearest one online and headed out. My daughter accompanied me and told me to "stay calm, things happen." She waited in the car as the car repair crowd seemed to put her off.
The guy was nice, helpful and made me feel less dumb by telling me his own tales of lost gas caps. He said that I should be happy I didn't drive off with the hose still attached to the car...
There were so many items I had never seen before in that store, and I am sure there are people that know exactly what to do with each one of them. Who would have thought there were 30 different sizes of gas caps. How is that, when the gas pump nozzle is just one size?