I like the idea that the character would quote Casablanca, but this is pretty vague. It doesn't tell the reader anything specific, which makes it hard to picture the setting. We have no idea who "he" is, where "here" is, or what the "situation" is beyond them meeting.This is a very rough starting so please be gentle. Im struggling to find my conflict;
It can’t be, why is he here? Off all the places in all of the city why did he have to walk into here. Actually that’s dramatic even for me; I don’t think this situation calls for quotes of Casablanca.
It's important to set the scene, particularly at the beginning of the story. We want to establish who, what, where and when. We want to establish the genre, set the tone for the story, and hopefully introduce some conflict. This opening suggests conflict, which is good, but I think it could do a better job of setting the scene.
If it were me, and this is just a suggestion, I would use the exact quote and try to do it in a way that helps to characterize the narrator. I can imagine a private eye thinking this, but it could be someone who just likes the movie. Either way, I would try to inject a little more attitude into the writing.
I returned from powdering my nose to see Marc sitting at the end of the bar, beer in hand and talking to Jane.
Of all the gin joints, I thought, borrowing a line from Bogey. What the hell was he doing here? I'd just wanted a fun night out with the girls. One night, and he couldn't even give me that.
Maybe this doesn't fit your characters or your story, but I like to give examples because I think they help to illustrate the point.
We get a better idea of who the characters are, where they are, and what's going on between them. At the same time, the narrator's voice, and her attitude toward Marc, is more pronounced.
Whatever direction you decide to go with it, I would encourage you to be more specific with your word choices. The quicker you can set the scene, the quicker you can pull the reader into it.