This is arguably the most popular trope in modern fiction. It provides built-in tension and a satisfying "thaw" as characters realize their preconceptions were wrong.
Conflict arising from what is unsaid rather than just external villains. SexMex.24.05.14.Galidiva.Step-Mom.Goes.To.Perv....
Emphasize the risk of losing a stable friendship for the uncertainty of romance. This trope thrives on the comfort and deep history characters already share. This is arguably the most popular trope in modern fiction