This very common yet harmful vice has become epidemic. Thankfully, there are many ways to fight it.

There is one sin, one vice, that has become epidemic in our day.

It’s the vice that causes political incivility.

It’s the vice that leads to many depressions and incidences of self-harm.

It’s the vice that (among others) causes Catholics — up to and including cardinals — to lead double lives.

It’s the vice that covered for sexual harassment at the highest levels of Hollywood and politics.

The vice is vanity — also called “vainglory” or “notoriety” — and we suffer from it when we begin to care inordinately what other people think of us.

It starts, innocently enough, with enjoying praise for a job well done.

It is fine to be praised for a job well done. It is right to feel healthy pride in a legitimate accomplishment, even a spiritual accomplishment.

But the trouble comes when the accomplishment becomes less important than the praise. Slowly, subtly, we start to long for admiration more than achievement.

We are guilty of vanity when we seek praise for its own sake, said St. Thomas Aquinas.

This happens at school, at work — and at church, when we start acting holy not for God, but to be seen by others. I noticed it when I read about a saint who would kneel in prayer in parish chapels, but quickly sit if he heard someone come in, so he wouldn’t look holy. Ouch. I kneel if I hear someone coming.

“A vainglorious man is a believing idolater,” St. John Climacus wrote. “Apparently honoring God, he actually is out to please not God but men.”

Social media hyper-drives vanity.

Cardinal John Henry Newman saw his world as particularly prone to vanity because of the “new media” of the time — daily newspaper delivery:

“Never could notoriety exist as it does now, in any former age of the world; now that the news of the hour from all parts of the world, private news as well as public, is brought day by day to every individual, as I may say, of the community, to the poorest artisan and the most secluded peasant, by processes so uniform, so unvarying, so spontaneous, that they almost bear the semblance of a natural law.”

Newman said “newspaper fame” lends itself to a second fault of vanity: Seeking praise for what is not truly praiseworthy.

You can be famous as a great statesman or a great criminal, he said. You can be known for philanthropy or for adultery.

In the age of social media, we can add to his list: You can be admired because you rescued a dog or because you took a cute dog picture; you can be admired because your child received her First Communion, or because your child looked spectacular in a party dress; you can be admired because you built a great restaurant, or because you posted a picture of a great restaurant dinner.

Vanity feeds political incivility, too.

Another way to be guilty of vanity is to seek praise from those whose judgment is not sound, said Aquinas.

We do that all the time. We seek out our own political bubbles on social media, where we bask in an echo-chamber of those who agree with us. There we find ourselves patted on the back for sharing disparaging comments about political opponents and lionized as brave souls for saying intemperate things about “our” issues.

This has the effect of creating an even greater distance between the worth of our convictions and the volume of the praise we receive for them — and confirms us in our contempt for all who disagree.

Vainglory ends in hypocrisy.

“The servant of vainglory leads a double life,” writes St. John Climacus. “To outward appearance, he lives with Christians; but in his heart of hearts he is in the world.”

Our vanity always accepts “the office of bishop or abbot or teacher,” he added. “It is hard to drive a dog from a butcher’s counter.”

This is why I pray that my children will get caught doing wrong while they are still kids. The longer you successfully appear good while doing wrong on the sly — whether you’re a secret drinker, an “incognito” pornography watcher or a small-scale embezzler — the deader your conscience will become and the further you will get from repentance.

But don’t despair. Healing is closer than you think.

“I have encountered some who embarked on the spiritual life out of vainglory, making therefore a bad start, and yet they finished up in a most admirable way because they changed their intentions,” wrote St. John Climacus.

Holiness has a ripple effect in our life. The more often we do the right thing despite what people think, the easier it gets to do the right thing despite what people think.

There are many ways to fight vanity:

• Turn off social media, if it is a source of vanity in your life.
• Come clean about your secret sin in confession and to an accountability partner.
• Do secret acts of charity that carry no reward.
• Accept humiliations.
• Pray the Litany of Humilityas part of your morning offering.
• Meditate on the Beatitudes weekly.

The meek shall inherit the earth — because the proud and vain will destroy themselves. The greatest glory is a quiet life of holiness, where you “perform” for an audience of only one: God.

His praise is enough.