Because they're a team!
Because they do live on the same planet.
Because Haley called godmother.
Because now they're sisters in law.
Because they can read each other.
Because they can open up to each other about Nathan and Lucas.
Because they both share a love for music.
Because Haley is the only one that came back.
Because Peyton was hurt when Haley left.
Because they spent dare night together.
Because Peyton produced Haley's new album.
Because they are business partners.
Because Haley came back.
Because they have the same taste in guys.

From othforums.com♥