An exceedingly painful accident known to occur in
Japanese sushi bars to customers who punctuate their words by waving
wasabi-coated chopsticks around -- especially if the person in question does not pay attention when he/she tries to put the wasabi-coated chopstick into his/her mouth and misses rather empathically. Also a stunt not likely to be forgotten by those privileged to witness it.
On a more serious note, go forth and regard the very wise Things You Should Never Do With Chopsticks.