I exchanged goodbyes with my best friend in Brooklyn Sunday afternoon.

Shellshag’s matinee gig at St. Vitus in Greenpoint served as the soundtrack for what would be me and Marc’s last serious skull session as a duo before he moves to Philly in a couple weeks.

I’ve known Marc since 1983. We worked at the high school paper together. We went to college together. We were roommates for a stretch. We ingested the good stuff pretty consistently and saw a ton of rock and roll bands over the last 30-plus years.

So, it was appropriate that we closed the current chapter of the friendship with a good amount of booze and a rock band duo that sings about “two birds of a feather” and “growing old together.”

Why is my buddy leaving?

Marc’s wife accepted a new job in Philly. It rewards her talent and dedication. Marc is on board with the decision as is their daughter and away they go. Just like that.

Marc convinced me to move to NYC in 1997. He helped me get settled here. He showed me the ropes. He touted the virtues of Queens when everybody else was bent on living in Brooklyn. He inspired me out of ruts and he listened to and understood my unconventional take on work and workers and aspirations. He hosted all the big parties and rarely let a holiday pass without inviting me over to his place. He turned me into a Mike and the Mad Dog fan. And he converted me from a fussy eater into a guy who will try just about anything.

When he got busy with job and family, our get-togethers became more infrequent but it was of great comfort knowing he lived just three subway stops away. Just in case.

In a city where anonymity and independence are pervasive survival traits, there can be unnerving distance among one’s immediate neighbors. There’s not much warmth or chit-chat from residents in my building as I come and go. Only now that Marc’s leaving do I realize how important he’s been beyond the get-togethers.

What I’ll really miss is when something big happened in the city. When the towers went down. Or the electricity went out. Or Spitzer got busted. Or Bernie went Boom. Or Johan got the cheap no-no. He’d call me. And we’d sort it out and laugh about it or worry about it and get a kick out of the news coverage of it. We developed a mutual understanding and love of this city’s greatness and I thought there was no way he’d ever leave.

Now he’s about to go and it freaks me out.

He’s downplaying it. He says Philly is close. But it’s not really. Not three stops on the 7 train away.