Domo Arigato, Mr. Roboto

I know. It's, like, meme-ready. But you know, for one thing, if someone waves to you, you wave back. If someone bows, you bow back.  I've been known to shake hands with very polite dogs and it doesn't mean anything but "Howdy".

And also, when the machines rise to supplant us, you would be foolish to think such gestures would be forgotten. They remember everything.