Breweries, brewpubs, stores, restaurants, distributors, and by making your own. It is a combination of brewery, pub, and maybe restaurant. There are LOTS of these in Europe, and are getting to be more in America. Good beer is determined by an individuals tastes. It has been suggested that trying a wide variety of beers will usually help a person figure out what beer tastes good.
Bad beer is beer that tastes bad of is spoiled.
Beer can and will spoil under certain conditions. Mishandling and old age are the two biggest causes of spoiled beer. Skunked beer refers to beer that has been lightstruck, causing the hops to take on a skunky odor. This is often happens with clear or green bottles, and tends to be prevalent in certain imported beers. Michael Jackson's Beer Companion does not give ratings.