Good, evil and zubar!

Although most people have an intuitive definition of good and evil these have as much meaning as zubar (word I made up). Here I am talking about good as the opposite of evil.
You see, it is always possible to see good/evil in any situation. To me this makes the words effectively meaningless. For instance most people would say saving a life is good. But their being one more life on the planet (specifically one at the top of the food chain) means other things will have to die to let it survive. It will consume resources that others could have had and it may grow up to be a mass murderer. Obviously I'm being dramatic but the point remains, there is no such thing as good/evil.
The only other pretend argument is that god is good and anything like god is closer to good. This falls apart so badly it's fun to mention. If I want to be like god (or good) then I should flood the planet and kill as many people as possible.
It's funny what happens when you try to define intuitive things, god disappears in a puff of logic... again!