Disgruntled ex-employee starts shooting, drops several people and then shoots himself or goes down from return fire. So commonplace, so “normal” — a thoroughly American way of dealing with stress, rage and unemployment.

And the more it happens, the more likely that the next whackjob will say to himself, “Well, if nothing else works out and if my ex-girlfriend continues to refuse to speak to me, at the very least I can start shooting and go down in a blaze of anger. And at the very least my rage will be visible and palpable and discussed by the media.”

The late Jeffrey Johnson, 53, a former employer of Hazan Import and a designer of women’s accessories, had been let go about a year ago, according to a City Hall spokesperson. The cops took him out on 33rd street soon after he shot his former boss, but not before a brief firefight. Mayor Bloomberg has just stated in an outdoor press conference that one or more onlookers may have been shot by NYPD friendly fire.

“The cold-blooded killer wore a business suit and was carrying a briefcase when he pumped a pair of fatal bullets into his victim near the 33rd St. entrance to the skyscraper, a witness told the Daily News.

“The well-dressed shooter, after casually strolling away from the murder scene, was gunned down within minutes in a…confrontation with the cops.

“There was blood on the sidewalk,” said witness Rebecca Fox. “It was like a scene out of CSI, but it was real. I was literally shaking.” Seven other people were wounded, none too seriously, before the shooting stopped just after 9 a.m.