According to Plato, how is our life similar to the lives of those who are chained inside the cave

For Plato, most of us are confined to a life in ignorance and seem to like it because we don't know better. People chained in a cave can only see the shadows cast on the wall against the fire, and think those shadows are the reality - because that is the only thing they have at their disposal. On the other hand, a philosopher can choose to walk outside the cave and see the reality (or as much of it as his senses would allow). His fire is not the cave fireplace: it's the Sun itself. Most people never get to see the Sun (which is a metaphor of the absolute knowledge). They never get to educate enough. For them, cave is the only realm there is, fire the only source of knowledge, and shadows on the wall the only thing they can see.