Pittsburgh officials are hailing its citizens for celebrating the Stanley Cup "responsibly" Sunday night ... except for the one moron who was arrested for harassing a police horse.
The Pittsburgh Public Safety Dept. says ... for the most part, people celebrated responsibly -- no riots, no pepper spray, no major incident whatsoever.
But there was SOME stupidity.
Firefighters were sent to put out 2 couch fires and a mattress fire ... and cops responded to a 20-year-old male who was "taunting a Pennsylvania State Police horse."
Cops say the moron who bugged the horse was arrested ... of course, of course.