Communism is bad because it is more of a theory than a valid practice; analogous to Capitalism's Laissez Faire. Socialism however is the theory of Communism used in practice. Some countries do it well such as Denmark and Japan, and some do not such as India and North Korea. The core difference (in my subjective opinion,) is the application.

Countries like Denmark, Germany, Canada, and so on operate under various applications of Market Socialism. This is a blend of Capitalism and Socialism where one endeavors to ascertain the best of both worlds.

I personally believe in the El Paso Taco Shell mindset. "Why not both?" This is why I believe a Socialist country like India failed at creating an equal economy the same way Calptalist America did; an unhealthy and obsessive dedication to an economic theory.

With Socialism, it is not the theory that is broken, but the application of it.