It appears that relationships go down one of two paths - friends or something else, and the transfer between paths is rocky and rare.
Why is this?
My ex and I started as friends. We ended fairly badly, but we’re still friends, although it took a lot of work to get there.
I think some of the problem is that we look for different qualities in our friends than we look for in a significant other. Much of the time, someone who’s a friend doesn’t fit the criteria for significant other, and vice versa. The key in finding a good significant other is finding one who fits both criteria, and that’s very, very hard.
First, it does happen. But certainly there are many occasions when it does not.
From what I have seen, it goes like this. We all have an image in our minds of the sort of person we date. This is not just about the physical, though that plays a part. Call it our internal checklist. This checklist comes from a medley of sources: some of these are explicit rules we lay down for ourselves: “I’ll only date people of my religion” or “I’d never date someone who smoked”, “I’d never be with someone who was cheating”. Some of these are just patterns that have developed without even thinking about them: in high school, I only seriously considered long-haired boys for potential crushes, and to this day I have no idea why. You see this all the time when people date the same person in slightly differnt form over and over and over again. My checklist has “plays roleplaying games and likes Dr. Who” on it. The reasons for this are complicated, and I don’t entirely understand them myself-- I don’t even like Dr. Who!–, but I never seriously considered being with a guy who didn’t know what the Tardis is.
When we meet someone, we compare them to our internal checklist. If they match it closely enough, we see them as a potential romantic partner. If we don’t, we put them in the “friends” catagory in our brains. Now, here’s the deal. If they do fit into the " potential romantic partner" catagory, and that is recipocated, then romance blooms very quickly: I mean, why the hell wait? There is no appriciable “friend” time, and once you are romantically tied, even that “friend” time is sort of retroactivly remembered by everyone involved as couple time.
I am going to assume that we are talking about an unrequited love situation: one person wants to be romantically involved ,and the other just wants to be firends. In this case, for the friends to turn into romantic patners, one of two things have to happen: either the person has to change to match the checklist, or the checklist has to change to match the person.
Some changes in the person are simple: the checklist may say 'no one who is married", and then the person gets divorced: it may say “no one who lives with their mother” and they move out.
Some changes are more or less impossible: the checklist may say “no one who is deathly allergic to cats”, and that’s not something that is going to change.
Some changes in the person are possible, but bode ill for the future: If hte checklist says “no one overweight” and the other person loses weight, it leaves a ticking time bomb.
Changes in the checklist are diffucult, but do happen. For reasons that I don’t understand, as a teenager my checklist included “tall and lanky”: I’d never articulated this even to myself, but everyone I was interested in was tall and lanky. That just disappeared when I was about 19. When I was about 21, men (as oppossed to boys) were suddenly on my checklist.
The important things to remember are these:
One: nothing on the checklist is a crime. Relationships are not equal opportunity, and they don’t work if either partner is patting themselves on the back for seeing past another partner’s shortcomings. It’s not fair that I woldn’t datw a guy that didn’t like Dr. Who, but it’s not my job to be fair.
Two: People don’t have a whole lot of control over their checklists. Superficial things can be unlearned: if you realize one day that you have been catagorically dissmissing anyone who is not a redhead, and that that is a stupid hang-over from your first relationship, which happened to be with a redhead, you can teach yourself to see the blondes and brunnettes in a room. But it’s hard to do, and it is extremly diffucult to even notice these patterns in the first place.
Three: Outside parties have no control over someone else’s checklist. It just ain’t gonna happen, If someone’s checklist includes “plays videogames”, then you can’t do anything to change that. That’s just the sort of person they see themselves with, and that’s the way it is. It may change by itself, but you can’t make it happen.
I think that one reason ‘friends first’ works so poorly is that it often involves one party who is romantically interested from the beginning, but who, out of fear of rejection, tried to ‘ease in’ to a romance by getting the other person to like them as a friend. The problem with that strategy, as other said, is that people don’t have the same criteria for friends and lovers.
When it does work, it think it is more of a mutual realization. People have to be genuine friends, without the ulterior motives of wooing – then if doesn’t happen, they don’t notice, since they weren’t looking for a romance.
I can’t answer the why of your question, I can only confirm that your observation is fairly accurate.
I’m sure for every couple you meet who were truly friend first (as in, they hung out together regularly as buddies), you will find plenty of others who could not make that switch.
My very own future Mr. C would not be “friends” in that manner with me – and stuck to his guns for three years. He did not want to get stuck in the catagory of a guy friend with me and so refused to be buddies like that.
We did get together every few months for lunch or dinner and kept up with each other that way, plus got to know each other more deeply. Finally I was ready to date him and now, more than four years later, I can’t wait to marry him.
So – there you go. One girl’s experience with a man who would not settle for friendship.
The day I met my current boyfriend he asked me for my number. I gave it to him, we went on one date, we decided we weren’t compatible (as a couple). Since we have a bunch of mutual friends (the NYC Dopers), we kept running into one another and we stayed friends. Nearly a year after we’d met, he came to a party I was throwing, I asked him out, and we’ve been dating ever since - over a year and a half.
Does that count as being friends first? 
Not only does “friends first” work for me - it’s the only thing that ever has. I can’t imagine wanting to date/be intimnate/have sex with someone with whom I wasn’t a friend. Twice has someone set my loins on fire by something other than words, without becoming friends first - but I wouldn’t want to actually try and forge a relationship with either of them until we’d actually become friends (which I have with one of the two).
Unfortunately, this particular set of weird wiring also means that most of the people who are my friends are people I would like to have sex with. sigh I just have to live with that.
Omirka would you be my friend?
Well, “friends first” worked for me. The transition phase was a bit bumpy, but really, I don’t think we would have ever, ever realized we were compatable as a “couple” if we didn’t spend 4 months just being good buddies.
Case study: Me. Of the 3 guys I’ve ever dated, all 3 started as friends.
There was Guy One, in middle school. It was hormones, and it as middle school. I think that says enough.
There was Guy Two, last year. Interesting scenario. Lasted for about two months, because what we both really needed was an emotional crutch for our respective scenarios. It worked fine, actually, because neither of us really wanted a relationship, we wanted a shoulder to cry on and I personally was in a desperate need for physical contact of some sort (long story). We got what we needed - emotional support and someone to make out with. We went into it firmly having talked it over, and with full expectations of: This is not going to last, nor do I want it too. There was a rough spot this past fall when he wanted to get back together, but we’ve gotten past that, and are still friends.
Guy Number Three started in January, and still is. At first, he was an instructor at my TKD school, then a friend, and then (maybe this past fall) I started noticing some attraction, as we started hanging out more (outside of a training environment), and we just grew closer. Fast-forward through a month or so of very awkward flirting, he asked me out, and thus, We Are.
Due to the fact that before we were friends, we were in positions of teacher and student of a martial art, it’s a relationship based totally on respect, not on attraction. My theory is that you become friends based on some sort of attraction (emotional or physical) and that builds respect (there are exceptions, of course), and that’s where problems come in - platonic attraction is very different than romantic. When that line is somehow crossed, things get very muddled up.
“Friends first” is working wonderfully for me. My boyfriend and I have been together more than 2 years now (we’re both 20), and we have actually been friends since we were 12. I think we have the best relationship of all the couples I know. We rarely ever even disagree, and I don’t think we’ve had a fight at all. He’s great 
“Friends First” has been working fine for me. My boyfriend and I were friends for a year or so before we started being more than friends. We’ve been a couple for almost six years now…