A panda walks into a café. He orders a sandwich, eats it, then draws a gun and fires two shots in the air. "Why?" asks the confused waiter, as the panda makes towards the exit. The panda produces a badly punctuated wildlife manual and tosses it over his shoulder. "I'm a panda," he says at the door. "Look it up." The waiter turns to the relevant entry and, sure enough, finds an explanation.
"Panda. Large black-and-white bear-like mammal, native to China. Eats, shoots and leaves." So punctuation really does matter, even if it is only occasionally a matter of life and death.
I'm reading this little book about punctuation right now. It's an absolute riot! I highly recommend it for the pedantic among us.