Father’s Day is upon us once again. That’s good news for the greeting card vendors.

In recent years, they have sold upwards of 100 million cards to Americans intent on paying tribute to good old dad. About half of those cards are purchased by dutiful sons and daughters. Wives honoring a man they love account for most of the rest.

Other merchants also rejoice in the arrival of Father’s Day each June because gift purchases keep cash registers humming.

The commercial side of Father’s Day, while good for the economy, is not all that important.

What really matters is taking the time today to remember how immensely important fathers can be in our lives, and finding personal ways to show dads just how special we know them to be.

Fathers give their children many things. The lessons they teach through example may well be the most critical gifts.

The vital mentoring role fathers fulfill was on the late former New York Gov. Mario Cuomo’s mind when he reflected on the crucial influence of his own father.

“I talk and talk and talk, and I haven’t taught people in 50 years what my father taught by example in one week,” he said.

The point Cuomo was making has been understood by great thinkers for as far back as human records exist. Some 25 centuries ago in ancient China, a great philosopher had a similar message.

“The father who does not teach his son his duties is equally guilty with the son who neglects them,” Confucius told his students.

In 21st-century America, too many parents are absent from the lives of the children they brought into the world. Others do not teach by example the lessons children want and need.

If your father is, or was, a wise and loving guide, honor him today.

If you are the father or grandfather of young children, resolve to teach them the lessons of character that will serve them well for a lifetime.