I love talking to three-year-olds. They're old enough to carry on a decent conversation, but not quite old enough to understand everything you say to them in the appropriate context. Take, for example, a conversation I just had with Ellie.
Me: Wow, there sure are a lot of toothbrushes on the counter!
Ellie: Oh, I put them there last night so I could count them.
M: Great! How many did you count?
E: All of them.
M: Ookaaaay...and how many were there?
E: (pointing at the row of toothbrushes) This many.
M: And how many is that?
E: blank stare
M: Did you count one, or two, or maybe five?
E: No, Mom, I counted all of them.