Some people have a knack for making you feel smarter for having listened to them.
Not only are they able to summon facts and studies, they make their points in a logical flow, and explain complex words if they use them.
They don't shove emotional rhetoric down your throat, instead calmly explaining their views and expounding on them when asked to do so.
Because of how prepared they are when questioned, it's clear that they have thought through what they are saying.
One of these people, whom I've been listening to for some time now (on YouTube, primarily), is Dr. Jordan Peterson.
I find his eloquent articulation of what he believes and observes to be highly compelling.
Some time ago, I bought one of his books - 12 Rules for Life - An Antidote to Chaos, and am making my way through it, having to pause every now and then to ponder upon what he writes in it.
Though this isn't exactly light reading, it's full of thought-provoking information, laid out in Dr. Peterson's engaging style of dry humour. I highly recommend it.