Why do girls with boyfriends flirt?

Anonymous
So there's this girl who shares a few classes with me... not really my type, but she's cute, and fun to be around. We flirt, tease each other, and one of her friends has flat out told me she likes me and I should ask her out. She certainly acts like it... one class, she was in front doing part of a project. I grinned and winked, and she completely lost her place for a few moments, all flustered. We've texted, and she's teasing and flirty.

Aannd... I've found out she's got a boyfriend. Not from her, because we were texting, I asked her if she was single, and she magically stopped replying. I asked one of her friends the next day (not the one that told me she likes me) and she confirmed that the girl does have one.

Why do girls do this crap? I mean, I'm not crushed, but she was fun to be around, and she wasn't even my type, but I still felt like asking her out. Why not even just reply and admit she has a boyfriend?

Updates
+1 y
Well I texted her again, "So what's so hard about answering a simple question and texting someone back? I'm not going to bite." She replied, ' :) lol, I know you don't bite. ;) '
Why do girls with boyfriends flirt?
6 Opinion