Why would someone start saying hi to you all of a sudden?

Anonymous
Like if you talk to this person sometimes, and they never say hi first, you're always the one saying it, and then all of a sudden they smile and say hi to you, every time they make eye contact with you, when they used to just smile at you when they saw you, now they actually smile and say hi. What could have changed? I mean they have talked in snapchat, and in person. But that just seems kind of odd? It could be that they're being nice, but why would it be all of a sudden? by the way, this is a boy and a girl, and the girl is the one who started saying hi all of a sudden. And they've known each other for a year now.
Why would someone start saying hi to you all of a sudden?
3 Opinion