We all know what good means as an adjective––pleasing, favorable, nice. But did you know that good is also a noun, meaning something that can be sold? This means a shopkeeper’s ideal is to have really good goods.
Good comes from an old German root for gathering, and in its original sense it means that something fits well. If something is good for you, it fits you well, or is healthy for you to eat. A long walk through a crowded city is good for someone who likes people-watching, but if you are a misanthrope and you hate people, that wouldn't be so good. If food has spoiled, it’s no longer good.