The saying goes You can't teach an old dog new tricks, but in keeping with our reptilian heritage, I think most people are unable to learn new tricks to teach. Sit, stay, shake, these are the extent of humanity's trick repertoire.
It's a bit sad we blame the dogs.
For my part, I'm teaching Dagon various tricks that play to his innate abilities. The first he learned was Protest!, in which he lays down like a politico. More recently he's learned how to imitate Humphrey Bogart. Next I think we'll work on having him walk like the Thin Man.