Some humans have perfected a way to avoid looking guilty in order to avoid punishment. But dogs can’t lie, they can’t manipulate, they are honest to the bone! So when you accuse them of something of which they are guilty they really look as guilty as hell!
However, their strategy to avoid punishment is much better than human. They don’t hide it, they just start to be as adorable and cute as they can be, and there is no way you’d have the heart to punish them. Just look at how Ralphie the Newfoundland admits his guilt after eating his brother’s toys! Could this be any more adorable?!