I realized this after reading a ton of shoujo mangas. Their plots tend to go like this:

1. girl confesses (or boy)
2. boy doesn't have feelings for girl (or girl doesn't have any feelings for the boy)
3. they get close and the girl keeps showing a cute face (or boy keeps showing a cute face)
4. boy falls in love with the girl (or girl falls in love with the boy)

It's a shoujo manga shortened to 3 boxes! :D