Both books and movies do this. On the theory that opposites attract, they put together two people with nothing in common, or worse yet, who actually hate one another, and call it love.
If you are writing a romance, you know it needs tension. Having your characters hate one another and bicker constantly can create tension, but is that really how true love begins? Or lasts? In a word: no.
John Gottmann at the University of Washington has found that couples with a ratio of fewer than five positive interactions for every negative one are destined for divorce.A story with too much lovey-dovey and not enough tension would be boring, and it turns out this is true in real life too. If you have a too high a ratio of positive statements for negative statements (13:1 or more), your affect comes across as insincere.
When I read or watch a romance where the characters are downright nasty to each other, where they insult each other often and compliment each other seldom, a little bell goes off in my head: I don't buy it. These people don't love each other, and even if they get together, it won't last.
You can have Opposites Attract. You can have Enemies Fall For Each Other. Just keep it real--keep more positive than negative interaction. (Yes, great sex counts!)
Another thing to keep in mind is scale. If the level of negative interaction is high and melodramatic, the level of positive interaction has to be equally melodramatic. That's true in real life as well as in writing. One of Gottman's other interesting findings was that fiery, fighting couples do work. They can throw plates at one another and shout insults, or (in books and movies at least) even duel with swords, as long as their make-up affair is just as dramatic and over the top--and still outweighs the negative bits by quite a lot.
At the other extreme, positive "statements" don't have to be verbal. You can have a quiet couple who demonstrate their love for one another indirectly. He knows her favorite muffin and always brings it too her. On the day, they fight, he doesn't say anything, but deliberately brings her the wrong muffin. When they make-up, he doesn't say anything either, but he has the right muffin.
But don't try to combine them. If he cheats on her with her sister, and she throws a knife at him and barely misses his throat, don't have the make-up scene be a quiet scene in which he gives her a rose and says, "I love you." Really, would that make it okay? No, way. She better find out that her sister used a love spell and then save his life from a three-headed wolf.
When it comes to plotting, the more problems you throw at your protagonists, the better, but be careful when applying this to romance. One of them can have a Big Secret, or even both of them. (I like it when both do, since it evens things out. One problem with a lot of Superhero romances is that the Superhero, almost always a guy, has this Big Secret which he keeps from his girl. She has only her frustration that there's something weird about him she hasn't figured out yet, and it makes her seem shallow compared to him. Sound familiar, Grimm?) But don't keep multiplying it indefinitely. If he has a gambling problem, and he cheated on her, and he's really from another planet, it's getting to be a bit much.
Finally, another pitfall to avoid is the Big Gesture that makes up (or is supposed to) for the Big Secret. Hollywood loves to do this. Guy and Girl quarrel for the entire movie. In the Low Point of the movie, they have one final blow-out fight. He moves to South America to be a nose surgeon and she proceeds to get ready for her wedding to the boy her parents like. (Who is usually much nicer than the jerk Hollywood has decided is the hero.) Suddenly, in the middle of rhinoplastic surgery, he realizes he loves her, gives his instruments to his assistant in the middle of the operation and runs to the airport. Then, just as she walks down the aisle, he bursts into the room, still in his scrubs, and cries, "I love you!" She ditches the man at the alter and runs to him and that's supposed to be how they begin their happily ever after.
No. No, no, no, no. This is so grotesque. Seriously, people, other than manikins in bad chick flicks, who behaves like that? Have you people never heard of a phone? Do not interrupt surgery, wedding ceremonies or flights at the airport to shout out your sudden revelation of affection and think that Makes It All Okay. All that does is prove your Bipolar Disorder.
What real people do is call each other up, or chat online, and hash out the issues and then get back together. If that's too boring for fiction (let's face it, it is) then come up with an actual and realistic dramatic moment that can showcase the characters' true feelings for one another. Don't manufacture drama out of thin air--it just comes across as thin.
Remember that cute song about the Yellow Ribbon? It's a great example of the Grand Gesture that works.