That only applies when the relationship implies bi-directionality. On Twitter, me following you doesn't necessarily mean that you follow me. Thus both direction

That only applies when the relationship implies bi-directionality. On Twitter, me following you doesn't necessarily mean that you follow me. Thus both directions are persisted in the model. If this were on Facebook, however, you would be right. (:User)-[:FRIENDS_WITH]-(:User) would only need to be persisted once and with an arbitrary direction.