A lot of great ideas come when absolutely nothing is commanding the brain’s attention.

Ideas for inventions came to Nikola Tesla as fully-formed visions so lifelike he once asked a man standing next to him if he could see it too.

Paul McCartney dreamt the melody for the song “Yesterday.”

J.R.R. Tolkien wrote, “In a hole in the ground there lived a hobbit” on the back of an exam while grading. It became the opening line for one of his most beloved books.

Then there’s me. I shouldn’t be left alone with my thoughts – ever – because a lot of awful ideas also come to an unfocused brain.

Like running.

Walking is an activity I enjoy because it’s the simplest and most effective way of getting me from the couch to the refrigerator then back again. I’ve walked for the past 52 years and like to think I’ve gotten the motion down by now. But when I heard my 14-year-old walking quickly behind me, I started running because that punk wasn’t going to beat his old man.

He did, of course, because after five steps something in my knee popped and it still hurts. I now groan like a sitcom grandpa when I get out of bed.

The idea of running on the street, unlike walking to the fridge, was stupid. Running is not the same as walking. It’s more like exceeding the speed limit while driving, and we all know speed limits were put in place to save lives.

History is filled with people doing things that sounded like a good idea at the time, usually after a few beers. I don’t mean epic stupidity, like getting involved in a land war in Asia, I mean little things.

For example, in May 2001, Todd Poller, 45, was fishing with friends when he unexpectedly grabbed a perch and yelled, “hey, watch this,” before attempting to swallow the five-inch fish, according to the Associated Press. The perch became stuck and Poller choked to death.

These things happen all the time.

In July 2016, two men walked off a 90-foot cliff in Encinitas, California, while playing Pokémon Go, reported CNN. They survived because they fell into the ocean, but they’re still stupid.

To try and make some sort of sense of stupid people, in 1976, economic history professor Carlo M. Cipolla of the University of California-Berkeley published the paper “The Basic Laws of Human Stupidity.”

In it he wrote the Five Basic Laws of Human Stupidity:

1. Always and inevitably everyone underestimates the number of stupid individuals in circulation.

2. The probability that a certain person be stupid is independent of any other characteristic of that person.

3. A stupid person is a person who causes losses to another person or to a group of persons while himself deriving no gain and even possibly incurring losses.

4. Non-stupid people always underestimate the damaging power of stupid individuals.

5. A stupid person is the most dangerous type of person.

We need more academic papers like this. Oh, and labels on legs warning people not to use them to run. Running is stupid.

Jason Offutt’s newest book is “Chasing American Monsters: 251 Creatures, Cryptids, and Hairy Beasts.”