What is the definition of good? There are as many as 44 definitions of the word 'good' in dictionary. But one of the most common definition of the word good is to do with something desirable, suitable etc. Talking of 'good' in this context leads me to think that the idea of good is highly relative in most cases and is often based on perceptions than on real facts. Even if we find something to be supposedly good, something better always shows up. In my opinion even something best doesn't remain best forever. For example, iPhone 2G was 'good' and soon was replaced by iPhone 3G then by 3GS and then iPhone 4. This is typically based on mass opinion, the sales of the product etc that it was easy to conclude the goodness of the product.
But talking about people - If there are some presidential candidates, each one of them are going to be good in their own way. But it is based on their actions that people are going to perceive them as good or bad. Something looks good till something better comes along. As a matter of fact when something better comes along even the 'good' looks close to ordinary. All this is fine as long as you are talking about a celebrity being good or better or even best. But when you are talking about interpersonal relationships. Good is often not good enough. Most people don't have a definition of good, which in my opinion would be highly idealistic; though I feel a fair idea of what one considers good makes sense. But there are additional factors which affect definition of good - previous experiences, situations, moods etc. So it is very human to overlook good and keep looking for better and best. When you fail to see 'good' how do you think you will find better and leave alone best. It is like - kissing several frogs to find a prince who probably doesn't even exist or who you just missed out constantly looking for better. Good is good enough as long as you are able to see through the goodness.
But coming back to how good is good. Well it completely depends on the person, their perception and opinion. Someone or something may look good to me, but may look really bad to you. So good has to do completely with how you look at something. Forget axiomatic and absolute stuff, they don't exist all the time. But 'good' is a very relative term and there is no correct definition of the word in my opinion. I want to finish by saying that since 'good' is more of an opinion/perception, don't get carried away when someone calls you bad. You are good as long as you consider yourself good. Since for some people nothing is good enough, its ok for products to be constantly redesigned and remodeled for people to like them, but for humans, it is completely worthless to constantly change yourself to please someone who themselves are not good enough but consider you as being 'not good enough.' So it is completely sensible to be yourself and not giving importance to someone who doesn't deserve it.