Some Communists experiments (not an exhaustive list, either):
Russia - Presumably "for the people", led to widespread famines and state sanctioned murder. After seven decades, had so little support that it couldn't prevent an ouster by unarmed civilians. Communists now call this "state capitalism".
Germany - An attempt to take over the country through violence backfired. Later, a radical forms a party made up of 'revolutionaries' that combines neo-communist ideology with racism. Playing on popular hatred of communism, he gains power - an then makes an alliance with his Russian cousins five years later. Needless to say, an infamous failure. Called 'fascism' by the Communists.
China - A popular peasant uprising against the mandarins leads to a society dominated by a secular imperial court. Communist dogma is used to justify what might have been the worst human disaster outside of WWII. Most recently, a popular movement against the government by idealistic students was brutally crushed. Have yet to hear what Communists call this one - still "communist", as far as I know ...
Cuba - A corrupt dictator is replaced by a Marxist revolutionary, who promptly becomes a corrupt dictator that outlaws the Church. An equality for most people income-wise is achieved by destroying what little economic activity that existed pre-revolution. The main export of the country turns from tobacco products and sugar to mercenaries under this long administration. Still a "communist" state, albeit with "qualifications", as per the Communists.
Vietnam - An unusually brutal group of revolutionaries systematically murders all who oppose them, inventing new kinds of warfare in the process. A group trained by them initiates one of the worst genocides in the twentieth century on the civilian population of Cambodia. After fighting to 'liberate' the southern part of their country from the West, invades two neighboring states four years later in a war of imperial conquest. Employing the same brutal means used in said "war of liberation", still takes twenty years to subjugate the indigenous population. The nation, once prosperous, is now a basket case - although it does boast the fifth largest army in the world. Popularly touted as a communist success story by many on the Left.
Korea - The North, ruled by a Communist oligarchy, is destitute. The South, ruled by an authoritarian oligarchy that is tolerant to private enterprise, is quite prosperous. The recent changeover of the latter to a more democratic political system will likely increase popularity and prosperity for the nation. There is little hope for the former, which is attempting to develop atomic weapons.
Yes, I am sorry. If we hadn't beat around the bush, and done something less 'reactionary' and more pro-active about this serious social problem, perhaps we could have saved the lives of millions of innocent people. Better late than never, of course.
Is my apology accepted, sir?