Booth And Bones!!!

They can't because if we stop waiting to see it happen ratings will fall!! Even though they would be an awesome couple!!

They wound find a way to keep us wanting more. Thats what they're experts in. All they'd need to do is make it a forbidden love or add a larger plot elseware or drag it out over a couple of episodes so that they introduce an issue that needs to be resolved over the series before they can become an item. I bet that as soon as they start to become loved-up, the Zach plot will reintroduce itself. Fox loves those two-part episodes.