'Community' Creator Dan Harmon APOLOGIZES -- I Was 'Dumb, Unclassy, Inconsiderate'

"Community" creator Dan Harmon says he's a "selfish baby and a rude a**hole" for playing Chevy Chase's voice mail in public ... and has issued a full-fledged apology calling the move, "childish, self-obsessed, unaware, naive and unprofessional."

Harmon just posted a statement on his blog titled, "Not That It Helps, But:" ... in which he admits to playing the tape for an audience of 150 strangers at an L.A. comedy club ... because he thought it would be funny.

"I was airing my dirty laundry for a chuckle."

But Harmon says he deeply regrets his decision ... explaining, "The giant mistake I made was involving someone else [Chevy] in that game of Russian roulette, someone that didn’t have an opportunity to say 'yeah, hilarious, let’s do this.'"

Harmon continues, "That was a dumb, unclassy, inconsiderate move on my part. I’m very sorry it’s reflecting poorly on the show.

Harmon says he's been paying attention to all of the critics who have been bashing him on Twitter ... and says, "Thirty people a day calling me an a**hole makes me know and feel, in my heart, that I am an a**hole. I’m a real “customer is always right” kind of guy in that regard."