M.I.A. flips off the audience at Superbowl, this is a big deal WHY?

So I missed the halftime show, being on a Greyhound and all. but come on, America. It's not like I couldn't just piss someone off by being myself and have the finger thrown at me as well. I mean seriously, when my brother and I played Nintendo as little kids, what did we do when Wario angered us? FLIP, HIM, OFF

what did you think of the Halftime Show? I really need to watch the damn thing!