How Can I Get Mad?

Daniel's new favorite thing is to run across the entire couch. Yes, this is unsafe and when I try to explain this to him he doesn't seem to understand or really care for that matter. In fact, whenever I sternly tell him "no" he looks up at me, gives me a BIG smile and says "Hi". The first time he did this I got a huge smile on my face so he must have remembered that. Ever since, whenever I try to reprimand him for running across the couch, he sits down, looks at me and says "hi". I managed to get it on video:

I mean, how can you get mad at that?