This is just my opinion and my guy friends in high school also told me this. This is pretty much what boys do when it comes to dating/flirting.

• First off, they aren’t only hitting on you, there’s other girls too. Boys always have a backup plan. When one girl doesn’t like them, there’s always the other one. So don’t be mad if you find out you’re not the only one, and besides it’s still the first stage: flirting. 
• Second. Boys won’t tell you directly that they like you unless they feel or you give them a hint that you like them too. They want to be sure. If you won’t show any affection they’ll eventually give up.  
• Third. What happens when two or more girls would like them? They weigh it out on which girl they like the most and who’s fun to be with. You would know when it’s not you. They would hardly text/call you.

Well, I guess that’s just about it. I think I missed some points. I’ll just update this post when I’ll remember it. lol. P.S; This is not meant to offend anyone.