Non-blacksmith turbonerd seeking information

Hello, blacksmiths of Reddit! I know absolutely nothing about smithing, and won’t be pursuing the craft anytime soon, if not ever. I am, however, about to run a Dungeons and Dragons campaign with a player whose character’s background involves smithing. I’ve planned a little moment in our first session where she can step in and correct a blowhard NPC who claims to know about the subject, but I’d like to offer her something more in the narration of that moment than “she corrects the blowhard and instructs him of the proper technique.” I figured I’d try speaking with actual IRL blacksmiths who can teach me a thing or two, or at least enough to craft a basic but realistic interaction for a fantasy tabletop game.

And so I ask: are there any blacksmith misconceptions or bits of misinformation in the blacksmithing community that persist despite your best efforts? If there are any, what would be the accompanying correction? Bonus points if you could explain it in a way that I, a layman, could understand.