I'm interested in the phrase 'not half bad', which, like 'cheap at half the price' actually means the opposite of what the user is generally trying to say. The term 'not half!' is commonly used to mean 'definitely', as in 'and the rest!'
So, when a person says 'not half bad' it doesn't make sense to me. It's like 'cheap at half the price', which literally means the opposite of what the user is trying to say.
What does the expression "Not half bad" mean? What do people use it to say?