... in some ways I felt a bit like FoD!Young/Rush kind of skipped the "in love" phase and went straight to integrated-personality.

Yes, this. There's not much mutual trust or liking, and then they're stuck together, and make it work. (Mostly. For values of "work" that include ascension.)

Like I said earlier in this thread, I think it's amazing that I started buying into the relationship even though they're both kind of... obnoxious.

*Cackles* SGA fandom does this trick too, with more comedy and lower levels of canon mutual dislike. It's pretty awesome.