A panda walks into a café, sits down and orders a sandwich. When he finished eating, he drew a handgun and proceeded to shoot the place up.
When the panda finished shooting, he headed for the exit, and as he did, the confused, lone-surviving waiter amidst the carnage, asked “Why?”. The panda produces a badly punctuated wildlife manual and tosses it over his shoulder.
“Well, I'm a panda,” he says at the door. “Look it up.”
The waiter turns to the relevant entry in the manual and, sure enough, finds an explanation. “Panda. Large black-and-white bear-like mammal, native to China. Eats, shoots and leaves.”
Although I have heard this joke an untold number of times... it still makes me howl with laughter.