Nothing is perfect.
It is also important
who and
how.
If you know what I mean, it will be clear enough to understand that not only the main idea of any Utopia is dangerous for society, but the ways of achieving it could be so different... and results could be so tragic... And, of course, it depends on people who rule the system... In USSR, since first years of revolution, it was clear for all clever people, that this idea ends tragically... Because of all Stalin's crimes Russia have lost almost the same amount of people, as during the Second World War, and it's not a secret... Yes, I know that many other nations think that Russia deserves such fate... I don't know... But I think that no one deserves to be blamed for the country where he or she lives. Such things (like genocide of any nation) should be a tragedy for the whole world, and not a "God's punishment" of "that bad country" or stuff like that...
I also think that bright people with pure minds have a chance to realize almost everything, but... It is inside us, we are making our own fate...
P.S. (Down to Earth

) I hope that any attemps of "building" a society of communism will fail without any violance. Yes, they will fail, because to achieve the communism we need one important thing... we need perfect people... huh... impossible.