my DM has a contract that he makes all new players read over. it sounds much more strict than it really is, but it goes over what is to be expected from both the players and the DM. the rules we have aren't about the kinds of games we play (more tactical vs character driven, silly vs serious, etc) it's about how the players conduct themselves. at the end of the day it's a game that we get together to have fun with, and if someone isn't having fun then it needs to be addressed.
my DM is running like 4 games concurrently (we meet weekly, the others less frequently). our game is almost always pretty screwed up in that he takes a very serious tone (with definite comedic relief) and has trained us to take our decisions incredibly seriously because there are ALWAYS consequences. we joke around about how he's given us PTSD because sometimes it feels like there are no right choices. Whatever we decide to do is going to end up making things worse.
but that's also what we signed up for. everytime we start a new campaign we spend a lot of time talking about what kind of game we want, and we all chose a game of thrones type game where everyone is morally gray and anyone can die at any moment. we make allies with npc's, become emotionally connected with them and they get killed.
BUT he's also running a "disney princesses" game for some of the players' wives. it's exactly what you think it is. he runs through his own versions of disney stories, it's almost like kingdom hearts? without the nonsensical plot... He's not really into disney, but he also knows that if he can get some of the wives to "buy" into DnD night, then they'll be much more forgiving about lettng their husbands play.
point is, it doesn't matter what kind of game you play as long as everyone had fun. one of the players in my game really enjoys combat more than anything... he likes everything else, but combat is the only thing that clicks for him, so to speak. so my DM always tries to have at least a little bit of combat every session. we've had games without combat that we all enjoyed, so it's not like he's a killjoy if there's no combat.. just that's his thing.
i DEFINITELY think there's an art to DM'ing. you have to plan the whole session, even if you're just pulling straight out of a book there's stuff you need to do beforehand. you also have to be able to read the room and make sure things are going smoothly. if you can get yourself a reputation in the community as being a professional about it, good for you