Sometimes, when I'm hungry, I'll meow by my bowl and there's some old, dry food in there - with no jelly left on the chunks.
I don't like these bits - they smell funny.
My human will lift the bowl up, to put new food in, and I get excited.
He sometimes looks in the bowl and says 'what a waste', but I don't know what this means.
He then puts fresh food in the bowl, with lots of jelly on it, and puts it down for me.
I run over to the bowl and eat, but sometimes... sometimes... I can smell the old, dry food underneath.
I sniff and sniff the bowl, then back away from it and look up at my human. He's left the old food underneath the new food. He thinks I won't notice.
I stare at my human until he does the right thing and removes the old food - keeping the fresh food in there, with some catty biscuits on top. Then I eat.