Over time I learned how the system worked. In every neighborhood there was a CDR, committee for the defence of the revolution. Members of the CDR surveilled. Generally, people knew when you went out, who you had over, some things you said.
You couldn't know when someone would know. Some topics were taboo, others were more risky. But the biggest factor was whether you were likely to cause a fuss. People who weren't important were allowed to blow off steam. But they were watched. And the day they rose to become a threat, the system had been on them for some time.
So you thought long and hard before doing something that would actually threaten the system, outside the bounds of what was tolerated.
Ending with a system that looked free, and many even described as free. Because in a lot of important senses, it was. But in very specific, important senses, it was not.