What will draw my characters together?

Regardless of how your characters feel about each other at the beginning of the story, at some point they must form a connection. But what will draw them together? I’m referring, of course, to chemistry — that potent magnetism that attracts people to one another.

Physical attraction, while important in a romantic relationship, is not enough for two people to form a meaningful connection. There needs to be more substance, more grit, as it’s that which will help the protagonist complete their arc of change.

All relationships, whether romantic or platonic, tend to be built on one or more of the following types of connections:

• A bond over shared interests or experiences
• A broadening of one another’s horizons
• A balance discovered between divergent personalities
• A shared admiration for one another’s values

Consider the trope you’d like to use, as this will impact the kind of connection the characters can form. What kind of connection would suit that romantic trope?