Most good DMs make excellent players, because they understand about table atmosphere and group dynamic, and have tricks at their disposal for balancing these things and keeping the mood at the table fun and engaging. A good DM will respect the flow of the game, and understand how important the DM's rhythm is for that - they'll help if needed or asked, or if the DM wants their input, but otherwise let's the DM keep control of the table, because they understand why that matters. A good Dm will also generally try to RP in a way that supports other players and gives them chances too play their own characters - engaging the quieter players in ways that they'll respond well to, and making room for them to play, without stepping on or crushing the more active and enthusiastic players who don't need that assistance to participate.
On the other hand... a sweaty DM, who likes to dominate their table, enforce rules bluntly or harshly, and who may be prone to treating the dm chair as a power trip, no matter how nice their world building or story-telling may be outside that, will be prone to the same thing as a player, most likely - they'll quibble rules, interrupt flow, challenge decisions and often be disinclined to respect the Dm's authority on matters because they feel they know what is 'better', and will insist on saying so during the game, rather than after it.
