Our dog has some strange habits.
We feed him twice a day, firstly after his morning walk, so usually about 11 a.m. The second feed is in the evening.
Quite often, he doesn't finish his food. Today, he left most of his kibble, eating just the tinned meat. Over the past few minutes, he's been fussing at me, in a "Why don't you fulfil my nondescript want?" kind of way. I noticed that he had plenty of food, so I sprinkled a few crumbs of liver cake into his bowl. He has now eaten all his food and seems satisfied.
The liver cake was tiny in quantity. If he's been properly hungry, he could just have eaten his food. It's as though he needs permission to do so.
He's like this if we ever leave him alone in the house. We always leave him with food and water, but invariably when we return they are untouched. He won't eat them until we are present.