A good listener is someone who cares about what others people say, but that's not enough, we have to show them that we are interested in what they are saying by looking at the person or nodding. We can disagree with what the other people say and that doesn't make us bad listener, just make us human.
If a people wants to encourage what the other people think we can smile and touch the person.
In contrast, a bad listener is someone who is always interrupting and is always making fun of what the others say. You can disagree, but you still should want to be a respected person.