Desire and dependence are excellent force multipliers in drama.
When we pit characters for and against each other, we can shade and colour their actions beyond black and white, beyond cause and effect. Overt decisions can suddenly be second-guessed. What we think we know is true can be called into question.
Teetering characters are more interesting, more compelling than the rigid and the sure. Scenes that unsettle expectations are more fun to write. And watch.
When one character absolutely loathes another but is inexorably tied to them to achieve a desired outcome, drama is born.
Similarly when a character loves another but must hurt them to attain a goal, drama is escalated.
Whatever any character gets must always come at a price.