My step-grandfather was jewish and when I was like 3 or 4 I was obsessed with trucks and construction equipment and he would point out trucks and call them the wrong type to get me worked up. He'd say "look, a dump truck" and I'd say "no grandpa that's a fire engine!"
He was a funny guy. But he lied because he loved lying, and he did it constantly as much as he could. How can you ever really trust someone like that?