Hepburn and Tracy
Well, in the nine movies that Katharine Hepburn and Spencer Tracy made together, there was always a power struggle. In Woman of the Year, Hepburn's character's career overshadowed Tracy's. Then there was the hilarious Adam's Rib, where they squared off in court. He complaind that she wasn't his wife, she was a "competitor." Of course, the very thing that drove him nuts about her is what attracted him to her. Their relationship wouldn't grow stale because of that "edginess."
In Desk Set (which scares me because it looks just like the first place I worked with computers), his job threatened hers. More tension.
And in the lovely Guess Who's Coming to Dinner, the last movie Tracy made before dying, they played a married couple who loved each other deeply, but went head to head over whether or not their white daughter whould marry a black man (in the era when that was socially scorned).
Maybe their onscreen sparks flew because their relationship was so heated in real life. They definitely had something special. What do you think it was? Because, I want to bring some of that heat and tension to my hero and heroine. Some of that spark.
Do you have a favorite onscreen pairing? If so, what do you think makes them dynamic?