The questions:

1. When I started shipping them
2. What I think their challenge is
3. What makes me happy about them
4. What makes me sad about them
5. What moment I wish had never happened
6. Who I'd be comfortable them ending up with, if not each other
7. My happily ever after for them

( answers under here for Mac/Nikki, Sam/Jack, Ross/Rachel, Remus/Tonks, Chandler/Joey and Daniel/Vala )