Whenever i talk about my views in politics people say i'm a lefty.

I want to understand what is this boogeyman called communism that will "take over the world". I live in Brazil and, for the average american, our free health care system is communism. Even some brazilians think it's bad, which baffles me because it helps a lot of people, myself included. Everyone who needs cancer treatment go through it, it's one of the best in the world (for this particular disease at least) and affordable private health care plans won't cover expensive cancer treatment here.

People here often talk about communism being bad, but what really is communism?

I grabbed the Communist Manifesto and Why Marx Was Right to read, but did not start yet since i have to finish the book i'm currently reading.

I never tried to understand these things because they are all over the place and it's a little boring to me, so i'll ask some basic questions here before i go further in this endeavour.

Please, try to answer without anger and pointing fingers. Because every time i read about these topic online, there is fight and everyone says different things and accusations runs rampant.

1. What exactly is communism in layman terms? Because for me it's all over the place. Everything that seems to care about people is put into the communist basket, but a lot of people call it a dictatorship. ELI5.

2. Why almost every average citizen (americans and brazilians at least) says it's bad?

3. My best friend is a school teacher and is a marxist. He says Joe Biden is still a terrible choice, but the only alternative to Trump and he is not a communist at all, but i keep hearing people call him a commie. WTF is he? If possible, ELI5 what he is and what he stands for.

4. Why there is right x left and no place for something in between? Is there a need to everything be one side or another to work? There is no middle ground in politics? Grabbing aspects from the left and from the right and co-existing in the same government is a problem?

5. A lot of people really think letting companies run wild and free is good. That the market will regulate itself. I think this is naive, because even now they do some really shady stuff. Just look at Nestle.
   Why people say that and is there some truth to this that i can't see? Is regulating companies a communist thing?

6. People say that communism didn't work when implemented and the other side says that it was not really communism. What is the truth here? It didn't work? if not, why it didn't? If it was not true communism, what it was and why it was not true communism?

7. Is there a country that is communist today?

8. What books about the left and the right i should read? Nothing too dense.