Did you know that hummingbirds hum because they don’t know the words?

I was in second grade when I heard that joke, and it’s the first I remember clearly.

“That’s supposed to be funny,” Mom told me during a French toast breakfast.

Humor was all around me growing up. Funny noises. Silly stories. Amusing dog antics. Comments that were funny only to family or close friends.

“Why aren’t you laughing?” Mom demanded.

“I dunno,” I mumbled.

So Mom asked what I did when I didn’t know the words.

“I hum?”

“Right. And that’s why hummingbirds hum.”

“Oh,” I said, thinking that if all jokes were that stupid, they weren’t worth taking seriously.

I have never quite figured out the value of spending money to laugh at comedic routines with all that humor around us. For one thing, these routines often have visual components, and my guide dog can’t be bothered to explain the visuals.

That’s a joke.

Last Monday, a choral conductor asked us basses why we were having trouble singing at the tempo designated by her waving hands. I told her that we weren’t used to singing the passage as quickly as she was conducting it.

“Well,” she told me, “you’ll just have to watch me more closely.”

“Of course,” I said.

The rest of the choir sat in stony silence.

“Come on,” the conductor said. “That was a joke.”

Humor is quirky, unpredictable, and personal. Values, upbringing, our mood, drugs, surroundings, and many other factors influence the laugh voltage of a joke or comedic routine.

While growing up, most successful laugh-inducers based their routines on jokes and stories built on individual experiences and foibles before branching out to often snarky societal commentary. Rodney Dangerfield. Lily Tomlin. Richard Pryor. Al Franken. This inside-out approach encouraged us to come out of our shells to follow them to uncomfortable terrain.

When Rush Limbaugh started his radio talk show in the 1980s, he also used this inside-out approach, poking fun at himself while engaging in snarky commentary, assisted by song parodies and Snapple commercials. But he stopped his self-mockery after Bill Clinton became president, and his commentary became much nastier.

Yet his Dittoheads laughed at his jokes that I gradually found to be not at all funny.

Twenty-five years later, humor is a divider as we withdraw into our rhetorical bunkers and engage in in-person and social media battles. We wield humor as a weapon, cheering when a poisonous barb hits someone whose politics we despise and claiming victimhood when our side is hit.

“Stop being a snowflake!” we shout at each other. “That’s a joke!”

Even President Cheeto (that’s a joke) has used this strategy. During the 2016 campaign, a journalist asked a spokesperson to comment on then businessman Trump’s asking the Russians to find Senator Hillary Clinton’s missing e-mails.

“That was a joke,” the media figure was told.

Hahahahaha.

But, unlike me, I’m sure many Trump supporters found that joke very funny.

Consider recent comments of Keith Olbermann, that misanthropic genius that ESPN has just rehired for their flagship “SportsCenter,” show — for the sixth time. He called Education Secretary Betsy DeVos a “Motherf—ker,” and said that Ann Coulter was a “guy (who) wants to live his life as a woman.”

Those, of course, are jokes; do you find them funny?

I don’t, although I confess the corners of my mouth beginning to twitch at the Coulter comment, given her lifelong career of bullying others she doesn’t like.

Then there’s Roseanne Barr’s most recent tweet-joke:

“Muslim brotherhood & planet of the apes had a babykvj.”

I didn’t find that funny, but some of Roseanne’s supporters probably did.

After the start of the predictable firestorm, Ms. Barr tweeted that she was sorry for making a bad joke about Valerie Jarrett’s politics and looks. Later, though, she blamed her tweet-joke on the Ambien she had been taking.

To which someone from Sanofi, the company who manufactures Ambien, tweeted, in part:

“Racism is not a known side effect of any Sanofi medication.”

I laughed out loud when I saw that tweet.

Even though it probably isn’t a joke.