Garlic! One of the best ingredients you can use in your cooking. However, there are two main challenges. First, it may add a bitter taste and spoil your dinner. Second, you may overdose the raw garlic and in the worst case create mild tongue burns.
Two main precautions should be taken to avoid garlic bitterness spoiling your food. The center of the cloves are rather bitter. To avoid this, cut the clove in half from top to bottom where the roots are and then remove the center part. This is easy to see on older cloves that are eager to become new garlic plants.
To hard roasting is another source for bitter garlic taste. Therefore, add chopped garlic as a second or third ingredients when frying something. Preferrably, add the garlic after some "wet" ingredients, which will cook the garlic rather than fry it.
Well, this is a matter of taste. However, I'll recommend to "know" the strength of your garlic as garlic is not just garlic. I once almost burned my tongue after switching from some wimpy chinese garlic to my current favorite - organic garlic from Spain.