Reason: Malfunction!
LoL! This made me chuckle

Glad you're liking the 4S! It really is a cracking package... but perhaps the phone the 4 always should have been. Oh well, we've got it now. Hurrah.

Someone was asking me about a song last night, they thought the name was right but couldn't remember what it went like. Without thinking I grabbed the 4S and said "Play We Found Love." Simple, and may even work on the 4 with its very basic speech commands, but it worked and worked fast.

I still don't think I'll use Siri much at all, but I'm surprised that I used it so readily. Apple have done well to put its presence into the consciousness of the customers... if it'd been a 'quiet' feature I'd not have thought to use it. So, bravo!