Herobrine is the embodiment of fear for a lot of people, so much so that they run away from him as soon as possible.
He is not sure exactly why they run away and he sometimes even pursues them so they never leave him.
He finds himself clingy to people he thinks he likes, not too much as he doesn't understand alot of common emotions.
He acts in creepy ways as he stalks, observes the player at day and haunts them at night for fun.
If only people actually gave him a chance...