I mean I probably need to watch it a few more times to catch the nuances that Sabin was referring to. I couldn't make a connection with the characters like I could with many other Allen works. It's gorgeous to look at though.
I felt the same, Zahveed, when I first saw it. I was perhaps a little younger than you, but I just found them to be at times weird, off-putting, and engaging in behavior that I found distant. I don't mean to sound condescending but I've found that improved my ability to love Manhattan was the years I've put on and the number of complicated relationships. It's a movie about timing. The whole thing takes place in the middle of an affair between a very supporting character (Murphy) and Diane Keaton. It's ostensibly *their* story. But by shuffling the focus to Keaton and Allen, it changes its scope, becomes a larger, vaster portrait of how love rolls into and over other people, how you get trampled by it. Manhattan never calls attention to this, which is its genius. Woody Allen gets a big speech at the end, but it's less about clarifying the theme than telling off a hypocrite friend he's found himself latching onto all these years in lieu of taking a chance on things. The Woody Allen character in Manhattan is, I believe, the purest distillation of his persona. He's obnoxious, fringe, he's always being viewed from outside sources rather than in Annie Hall where he actively redefining his universe. And Diane Keaton sorely deserved her one career Oscar for this movie as a far, far more complicated woman.
More so than Annie Hall, Manhattan is the movie of Woody Allen's oeuvre that people have been copying the most for years. Every filmmaker wants to remake Manhattan. It's worth noting that Woody Allen hated the film and told United Artists (?) that he would make the next movie for free if they just disposed of it. It may not have cleaned up at the Oscars but he won the most directing awards from critics of his career (in a year of Apocalypse Now! amongs others no less). I think 1979 has to go on record for most egregious cinematography snubs. Neither The Black Stallion nor Manhattan were nominated.