OK, during an incredibly boring maths lesson, I came to a sort of conclusion about Ross and Rachel, and what the writers are thinking. (Sort of)
In TOW The Morning after, it was implied that Rachel still loved Ross, but was just mad at him about the whole 'Chloe' thing. (This was actually confirmed in TO At The Beach.) Now we are never actually told that they had fallen out of love, so to speak, which I think is quite a significant point. (Well *I* do anyway!)
In early series 4 they had many arguments, but they were more based on jealousy, and they seemed, to me, to get over it fairly quickly. In TOW the Fake Party, they seemed so much more like best friends than ever, and Rachel was treating him like a human for once. Of course she was in love with him at the time, but I think she's nicer to him when she doesn't know that she's in love with him!
Once the wedding had been and gone, Rachel told Monica that she was going to tell Ross that she was in love with him. Monica made Rachel feel guilty for being in love with him, and she tried to stop her from telling him. I know he was married, and trying to patch up a marriage, and it puts him in an awkward position, but you do stupid things when you're in love. Also, he NEVER told her that he didn't love her back, but instead there was rather a sweet line where she says 'Thank you for being so nice' and he replies, 'No! Thank you for... thank you'
Well, in parts of series 6, (Don't worry, I'm not gonna spoil it for anyone) the writers seem to be making Ross and Rachel (look, I'm being vague! :)) think that having any loving feelings for each other is a bad thing, and that they must feel incredibly guilty if they do.
I think that in reality they would be back together by now, but in sitcom land, there are important factors to consider:
1. The writers are waiting for sweeps or the finale episode(s) 2. They don't fall in love at the same time. (Amazing coincidence!) 3. They seem to be under the impression that the other one doesn't love them, especially if they do love them. 4. If they are in love with the other, and the other doesn't know, they are teased about it mercilessly by their so called 'Friends'. 5. They think that if they get back together it will get too complicated, which I can understand, but they could at least give us fans *something* to chew on!
I hope I haven't given anything away about series 6, I've tried to be as vague as possible. :)