There are two kinds of people who want to be DMs. Source: 25 years of tabletop RPGs and more than a few real life experiences.
The ones that want to make things fun for everyone, want a good laugh, and want people to be involved into their characters or the campaign. Those ones will leave you either crying your soul out at the end of a session, or will leave crying with laughter after one night passed being literally unable to catch air as you were laughing that much for hours at time.
And yes, it happened to me, and I'm not an easy public.
The second type are the ones that are sociopaths and want to control people and feel it's a good way for them to indulge in their fantasies of controlling people.
The two kind are irreconcilable. I have never, ever met someone that was both. Either they're the good ones, or the bad ones.
Protip: the bad ones often joke about being the "master" of the tables and being able to kill PCs easily, because it makes their peepee happy. It's a joke in the same way that "haha wouldn't it be funny if you showed me your feet :) haha" is. One or two jokes on that level is fine, and can be made by excellent DMs, but repeated offense is a clear cut case that you've got one that fap at night on their own power. No matter how ironic they make the comment.
Now, sociopathic DMs can be decent DMs, but they really don't care about the craft, they only care about the power the craft is giving them. So they're often subpar DMs, in comparison with the ones that care.
The ratio is, I'd say, roughly 50/50. Maybe a little bit more biased toward sociopaths.