A wine is considered "good" when it has a balance of flavors, aromas, and acidity. The wine should also be without any defects and have a pleasing finish. Additionally, a good wine should be true to its varietal character and reflect the terroir from which it came. A wine's quality can also be determined by its aging potential and how well it pairs with food. Ultimately, whether a wine is good or not is a matter of personal taste.