It’s never too late for a good belly laugh.

July 1 was, unofficially, International Joke Day. The origins of the day are unclear, but whoever started it was on to something – because our country sure could use a good belly laugh about now.

Which reminds me of the man who walked into a dentist’s office one evening.

“I think I’m a moth,” said the man.

“I’m sorry,” said the dentist. “But I can’t help you. You need to see a psychiatrist.”

“I am seeing a psychiatrist,” said the man.

“Then why did you come to my office?” said the dentist.

“Your light was on,” said the man.

I’m not sure where or when social media started making us more strident. But as we share ever-more-angry news posts that demonize those with whom we disagree, we are sacrificing our sense of humor.

The political jokes of many late-night comedians appeal to half of the country as their snarky nature polarizes the other half – which means those jokes are sarcasm, not humor.

Humor doesn’t take political sides. Humor brings us together.

“Anthropological studies have shown that laughter evolved as a way for humans to signal friendship and as a way to create and strengthen ties with a group,” reports timeanddate.com.

Which reminds me of the time Sherlock Holmes and Dr. Watson went camping.

They pitched their tent and went to sleep.

In the middle of the night, Holmes woke up and said, “Watson, look up and tell me what you see.”

“Millions of magnificent stars,” said Watson.

“And what do you deduce from that?” said Holmes.

“That life may exist on other planets?” said Watson.

“No, you idiot,” said Holmes. “It means somebody stole our tent.”

In his book “Anatomy of an Illness,” Norman Cousins reported that laughter helped him cure his serious collagen disease.

Since then, scientists have discovered that humor really is good for our health.

Laughter produces pain-killing endorphins. It strengthens our immune system.

“A good belly laugh increases production of T-cells, interferon and immune proteins called globulins,” reports PsychCentral.

It also decreases stress.

“When under stress, we produce a hormone called cortisol,” reports PsychCentral. “Laughter significantly lowers cortisol levels and returns the body to a more relaxed state.”

But we aren’t laughing enough.

Which reminds me of the three fellows stranded on a deserted island. One morning, a magic lantern washes ashore. A genie pops out and grants each of the men one wish. The first fellow wishes he was off the island and, poof, he’s home. The second fellow wishes the same and, poof, he’s home too. The third fellow says, “I’m lonely. I wish my friends were back here.”

The wonderful thing about humor is that it is infectious. It promotes good will, thoughtfulness and civility.

Regrettably, rudeness, anger and hatred are also infectious. They agitate us and tear us apart.

We must choose humor. We must rise above those who seek to agitate and divide us.

We must use social media to share fun, uplifting content, rather than derisive and divisive content.

Here’s a start:

A three-legged dog walks into a bar and sets his pistol on the table.

“I don’t want any trouble,” says the bartender, nervously.

“I have no beef with you,” says the dog. “I’m looking for the man who shot my paw.”

Tom Purcell is a Pittsburgh Tribune-Review humor columnist and is syndicated by Cagle Cartoons. Email Tom at Purcell@caglecartoons.com.