Everyone from about 25-40 loves the Muppets but they are not popular at all outside of that.
My kids - ages 6 and 8 - think the Muppets are hilarious and loved both of the reboot movies. That inspired me to show them a few of the original movies, which they also loved.
				
. So, looking the Muppet, which is moving, in the face and in the eyes, is pretty much instinct, even without an actor's training.