The face says it all

Nothing. The kid probably loves it, by parental unit suggested trying something different and kid said "I don't like it" just because she thought it was different. Parental unit used kid for social experiment.

Or maybe the kid doesn't like apple juice, so the parent replaced the soda with it so the kid wouldn't want to drink soda after trying it (since soda isn't healthy).

Or when you're expecting one thing so your brain gets all worked up and then disappointed