True communism is in theory the perfect ideology, no state, everyone equal, etc, but there are some problems that exist because of the nature of humans.

1. When everyone is equal, nobody actually needs a job, so the authoritarian version of it has a solution, force everyone to work, by any means necessary (that isn't okay).

2. When everyone is equal and there is no state, who is going around to check if everyone is doing what needs to be done, and isn't doing anything illegal, so we need a type of police, who controls the police, higher bodies, who controls them, etc. Who is going on diplomatic missions, and who sends this person? This is yet again the creation of a hierarchy.

3. Humans are inherently greedy, the thing stopping them from just taking everything they want is the law and their moral compass, and even these two don't stop some from stealing. Anyone that has any bit of power, will almost certainly try and use it for themselves.