If I'm eating a banana, Elijah wants a banana. If I'm eating a sandwich,
he wants a sandwich. It doesn't matter if he was happily eating cheese 30 seconds ago, if he sees me with something different, he wants it and wants nothing to do with the food that had previously been more than adequate!
At least this means that he's getting more adept (read less messy) at self-feeding with all the practice he's getting.