Personal Ads (idea for fiction film)

So I had this idea while I was listening to the song "Personal" by the band Stars last night and wanted to throw down my thoughts before I forgot them. I was thinking it might be cool to revolve my fiction film project around a failed meeting of two people (a male and female) who have written personal ads looking for someone. Rather than have them meet and fall in love, I could show an unforeseen circumstance preventing one from reaching the other at a set time to meet one another, ultimately shattering the hopes of the other person. Depressing huh? I don't know if I would have enough time to establish this, but additionally I thought it would be interesting if both the male and female characters were coming from some sort of hard or troubled lifestyle prior to seeking companionship...so that the finding of another person would represent a lifestyle change for the better, and failure to do so shows them no other direction than back to what they were before. I don't really want to make a happy-go-lucky film (this probably surprises any of my close friends that may be reading this as I tend to be a very happy person), but I think I would enjoy shooting something dark. I don't know. Just some thoughts on my homework!