Did I Ever Tell You?

... about the time I pulled up to a drive-in window at a local fast-food establishment and ordered a large drink and the person taking the order told me she couldn't give me that because they only had small and medium?

Can somebody tell me why that isn't funny? I still recall my difficulty keeping a straight face. Truthfully, I thought at first she was deliberately making a joke, and I was momentarily impressed with her cleverness. Until I realized she was serious and had no idea why her response was funny.

After telling this story a number of times, I have yet to find anyone else who thinks it's particularly funny. Can someone please explain, why not?

For awhile I thought that would be my magic pea. Like in the story the princess and the pea, only I was looking for a prince and the pea was a fast-food story that nobody thought was funny. Except me. And, of course, the prince. Whom I haven't found, yet. Apparently.