What qualities does a good listener have?

A good listening skill is always an important skill you need in anywhere we go. We stereotype that drug users are crazy and out of their minds and thus we try to avoid them. However, what if that is why they relieve stress using drugs instead of socializing with others, because we, the ignorant people are neglecting and disregarding the drug users' desires to engage in a deep conversation about their addiction and how to solve them. I think the most important skill needed to be a good listener is simply to listen to what others have got to say. Being prepared to listen to others is an essential quality that any good listeners have. And after listening to what the other person had to say giving a good constructive criticism or a feedback is always a good factor when engaging in a deep conversation. These are the qualities that a good listener must have.