Every good olive oil needs to have three things in common:
Olives are fruits after all, so good olive oil needs to have the aroma of fresh fruit. The olive oil should smell fresh and fruity, not heavy and 'oily'. When tasting good olive oil, you should notice aromas of green olive fruit, fresh-cut grass, herbs, artichokes, cinnamon, tropical fruits, to name a few.
Hopefully, your olive oil tastes bitter! Bitter is good, actually bitter is a great, positive thing in olive oil! So any fresh, high-quality olive oil must be bitter, which you will perceive on the tongue.
Depending on your taste, you can find an olive oil that will suit your palate most—the right balance of bitterness and fruitiness that you can tolerate.
Finally, good olive oil should be pungent. Olive oil pungency is that cough-inducing sting on the throat caused by the healthy phenolic compounds in fresh, high-quality olive oil. Many people think this is not good, but pungency also signifies the presence of certain antioxidants.