Juice? I'll Get You Juice!

Today I was practicing Get the Juice with Isaac, where he gets me a juice box from the fridge. He is now obsessed with getting me juice. Every time I start to tell him to do something, without listening to see what I am actually going to say, he guesses it will be "Get the juice!" and he runs for the fridge. Then he looks confused about why he doesn't get a treat when he delivers my juice (I only treat when he does it on command).