So there I was, listening to music with my bluetooth headphones, while surfing on the net with my unlimited data with the screen brightness set to high on my iPhone 3GS. I was surprised to see 10% go by after 10 minutes. Am I the only one? Oh, the funny thing is, for the last 10%, I found my iPhone mysteriously shutting down. I opened it again, then it shuts down after 5 seconds.