Those infuriating film-set street closures finally sent someone over the edge.

A hulking Upper West Sider on an errand to buy paint for his kid’s bedroom was so angry at being forced to walk around a massive movie shoot that he crushed a puny production assistant with a head butt yesterday.

“I live here! I pay taxes!” fumed the 6-foot-4, 285-pound Breffny Flynn, 43, who lost his cool at around 11:30 a.m. on Broadway at West 102nd Street, where a film crew was shooting “Premium Rush,” an action thriller starring “Inception” actor Joseph Gordon-Levitt.

Flynn went ballistic when production assistant Steve Lafferty told him he had to wait a few minutes to cross the street.

“Don’t tell me what to do, motherf- -ker!” he yelled, according to witnesses. “I gotta get to the store! I gotta get to the store!”

Flynn clenched his fists and puffed out his chest before landing the powerful head butt on Lafferty’s face, witnesses said.

“There was a big gush of blood,” crew member Michael Singleton said. “It looked like his nose was broken, and his eyes were puffy.”

Lafferty was taken to St. Luke’s Hospital. Flynn was arrested for assault and released with a desk-appearance ticket.

Flynn’s wife told The Post that the production assistant had first pushed her husband, who was headed to a hardware store for paint.

Most people only dream of head-butting their way through the ubiquitous film sets that have become as loathsome as tube-sock street fairs.

New Yorkers have long griped that the shoots eat up street parking, blast neighborhoods with floodlights and cause major traffic snarls in residential areas.

And for most jaded locals, the chance of a celebrity sighting doesn’t make up for the loss of a parking spot.

Mayor Bloomberg bolstered the film industry by offering a tax credit to producers who used New York City as a backdrop, bringing film and television production here to a record high last year.

“I certainly understand that frustration,” said Elisa Sansone, 46, who was walking on Broadway near the scene of the dust-up.

“People in New York are so directive that when something intervenes, it freaks them out. And look at these [production assistants] — they have a power complex. It’s intrusive.”

But Lafferty, who was released from St. Luke’s Saturday afternoon, was just doing his job, according to witnesses.

The film crew was in the process of shooting a complicated action scene that involved a bicycle messenger traveling southbound on Broadway, while a camera mounted on a vehicle filmed from the northbound traffic lane.

The thriller, set to hit theaters next year, centers around a bike messenger who catches the attention of a dirty NYPD cop after picking up a parcel from Columbia University.

Lafferty’s job was to keep the six-block area clear of pedestrians and vehicles.

“It’s the PA’s job to protect everyone on set,” an extra said. “This was clearly a safety issue.”

Gordon-Levitt and co-star Dania Ramirez were not on set at the time.

Additional reporting by Erin Calabrese