I have read it is better to remove the core of a clove of garlic. I actually see no reason for doing this. Does it have a different flavor, or is there some other good reason for it?  -edit- In addition to the question as reaction to the answer 'because the green middle is bitter', I was wondering:  -Then should you only remove the core when it is green, and not if the garlic is still very young? -Is there some easy way to remove this core? 
The green shoot in the middle of a clove of garlic is said to have a somewhat bitter flavor. 