We could make up plausible origins. Like old men shaking their canes at kids on the lawn, or children going after fruit trees with a stick–really good trees would have more fruit than you could shake a stick at…
You mean…
“More than you can shake a stick at” comes from Ireland, and the old Irish writing system of Ogham, where histories were inscribed frequently on long, thin, rods.
In Ireland, writing was typically limited to the druids, bards, and warrior classes, but the most prolific writers were the bards who were often grandiloquent when writing the genealogies and histories of the Irish families. In fact, some historians believe that the Irish love of story may date back to this time.
One of the old record keepers, a contrary man named Midac, received the rods for the Bascna clan–more specifically, he received numerous rods detailing the exploits of the warrior Fionn Mac Cumhaill, mainly submitted by Finegas. Midac made disparaging comments about the histories, saying that some of the stories were exaggerations, if not outright lies.
As Midac the Cranky was not particularly popular, and his comments were seen as disparaging not just Finegas, but bards in general, others started submitting tales of Fionn’s exploits for the sole purpose of irritating Midac. After a particularly ridiculous tale involving the Morrigan, Midac said that all the other clans had a handful of tales to their histories “a reasonable number” but the number of rods submitted for Fionn was ridiculous. Standing up and shaking the rod with the latest offering, Midac said that all these Fionn tales were more than he could stand and the way things were going, Fionn tales would be the only history of the people that would survive.
It was later that evening when one of the junior bards, after perhaps a bit more mead than was good for him, reenacted the scene. Unfortunately for him, when he mimicked Midac’s rage over the Fionn rods, he grabbed a heavy walking stick as a substitute, and knocked himself unconscious. It was this telling that took the fancy of the local population, and eventually led to our modern saying.