Cops should “take a deep breath’’ — and close their eyes — when dealing with angry people, according to the NYPD’s new “retraining’’ program.

The potentially dangerous advice is part of a $35 million “smart policing’’ primer by Mayor Bill de Blasio and Police Commissioner Bill Bratton that most of the cops who have gone through it say is completely useless.

One cop who sat through two full-day programs called them “not realistic’’ and “pretty silly.”

At one point during the lectures, the cop said, those in attendance were given breathing exercises to learn how to calm down — even when facing someone who could pose a threat to their safety.

“They said if you find yourself in a situation that’s getting heated, take a step back, close your eyes and take a deep breath,” he said.

“That’s pretty funny — that I would close my eyes in a tense situation.”

Another cop called the lectures “smoke and mirrors” to appease the public.

“They want you to stop and think about everything before you do anything, but a lot of times cops have to make a split-second decision, and they don’t have the luxury of stopping and thinking,” the cop said.

The officer said he was paid overtime to attend the retraining program. Other cops have been going to training sessions instead of their regular shifts, sources said.

Both cops said they — and everyone they know — gave the lectures low marks on surveys they filled out after the program.

The Post reported exclusively on Sunday that many cops have been falling asleep in their seats as they listen to the lectures at the brand-new, $750 million Police Academy in Queens, and that about 80 percent gave the program negative reviews afterward.

A high-ranking NYPD source said the lectures were “boring” and a “big disappointment” to cops who thought they were going to learn “real, hands-on, quality training on how to deal with a hostile prisoner or arrestee.”

De Blasio has promised that his retraining program “will have an impact on millions of people, because every interaction that every officer has with their fellow New Yorkers after they are trained again will be different.”