BAD IDEA
Can I say hello to an extraterrestrial?
Yes, but only if you want to be the galaxy’s biggest weirdo or start an interstellar incident.
Sure, you can say hello to an extraterrestrial — if you ever meet one, which hasn't happened yet unless your luck is insane. Just remember, they might not appreciate your Earthling greetings or your terrible jokes. So, consider your choices carefully before alienating potential invaders or friends from space.