I am sorry I should probably know this but what do you mean by 'the time Harry's head snapped his way so fast'?
Listen. So the band was performing at the iHeart release party in 2013. Ryan Seacrest was hosting and talked to the guys on stage. He proceeded to ask them about ‘What did you guys think of each other when you first met? Did you get along with one another when you first got together?’ and Louis replied. Just briefly *cough* mentioning how they went to a certain someone’s house to get to know each other better (please note Harry’s head snap in the second gif and his reaction in the third gif..):
I’ve never seen him react that instantly before, I mean look at how fast his head snaps around! Like please Harry, calm down ;)
Harry: It’s not necessarily an obvious thing about someone that makes you like or love them. It’s the combination of all the little things they do, in terms of things they do with their face or things they do when they’re laughing, or something like that…. (16 Nov 2013)