And also contrast that with Lana Lang, who will slowly drain the life out of a character and every scene she has with them until they are as dull as she is (Lex used to be my favorite character, but this is easily his worst season simply because all his scenes are with Lana now).
Right then, I'm feeling ambitious, so spoilers for DS9, Smallville, Superman Returns, JLU, Buffy/Angel, Fables, Gilmore Girls, and many different forms of Spider-Man (616, SMLMJ, Ultimate, and the movies).
Why do we like romantic relationships? They're passionate, intense, and can generally be a lot of fun when they're being set up. You think to yourself "Oooh, these two would be so good together!" or "If only blah blah blah, s/he would finally find true happiness with him/her!" Maybe you yourself will get swept up in the romance. After all, a strong part of fandom is being a shipper. Maybe it's wish fulfillment.
Planned linear love stories are good, they have a beginning, middle, and an end. Take Bigby Wolf and Snow White. Sure, there was angst, but that was all resolved, the two got married and lived happily ever after (well, okay, they still might not, but, as of this writing, they're happily married).
Serial fiction is tough, though, because you want to prolong the "juicy" part of a relationship by having both parties in love with each other but having some big obstacle in the way. So you spin the wheels and do the "will they won't they" lather rinse repeat thing until your series is over. That was John and Shayera's problem.
Or take it a step further and have your couple get together, break up, get together, break up, have sex, stay broken up, whatever. Clark and Lana can be VERY annoying just because of this fact. And a lot of the time, it just shows lack of imagination and creativity.
Why do a man and woman like each other? Because they do. Why should we root for them to be together? Because we're told to. In the Spider-Man movies, we're told that Peter is this great admirer of Mary Jane, and because he's the hero, we're supposed to want him to get her. The same can be said for Superman Returns. Superman x-raying Lois' house isn't creepy because he's lonely and a good guy, so it's okay. But what's wrong with John Jameson and Richard White? They're not the hero. Mari isn't Shayera, Shakar isn't Odo, and sometimes it's as simple as that.
The problem is, it's TOO simple. OTP has a sense of inevitability about it, doesn't it? A couple is fated to be together because the writers are encouraging it and grooming the fans to want it enough so when it finally happens, it's satisfying to all.
Right? Not really, because "when it finally happens", then what? The couple gets married and lives happily ever after? Nah, let's cause more angst, a hidden element, a death, anything. I was tempted to time how long it took from the Green Lantern/Hawkgirl kiss in "Wild Cards" to Hro Talak's appearance in "Starcrossed" and the Wesley/Fred kiss in "Smile Time" to Fred's infection in "A Hole in the World". I've seen fight scenes that lasted longer than those relationships.
And I'm not trying to sound like Joe Quesada here, who says the worst thing that happened to Spider-Man was his marriage to Mary Jane. Spider-Man isn't a romance book. Spider-Man Loves Mary Jane is a teen romance book, and it does that damn well because it's about Mary Jane more than it is about her true love (whether that's Harry, Peter, Spider-Man, or someone else, we don't know, she hasn't discovered herself yet). Ultimate Peter and Mary Jane's relationship has boardered on Clark/Lana for a while now because even though MJ knows he's Spider-Man, there's still drama keeping them from being together. And Peter and Kitty are more fun anyway, maybe BECAUSE you don't think they'll inevitably end up together and whatever happens is unexpected.
I think I should wrap up about now. Romantic relationships can be done, and they can be done well, but it's so much easier to draw things out, play them for all they're worth. Cause angst can make the viewers hurt with the character. Lorelai and Luke are perfect together and they're finally engaged. Good? NO! Give Luke a long-lost daughter and keep them apart!
Friendships and partnerships are fun and even more approachable than romantic relationships. Get Batman and Superman, Spider-Man and the Human Torch, Green Lantern and Green Arrow, Dr. Bashir and Chief O'Brien, and they all play so well off each other that it's much more entertaining. And one isn't going to be killed off just to make the other one hurt. Maybe I just think all the fun has gone out of fictional romance, maybe I think it's too formulaic most of the time, in any case, I've said my piece.