Dungeons and Dragons

They're just different. Sometimes you want to play Lord of the Rings, with a reasonably clean beginning, middle, and end. There'll be side quests and diversions, but a pretty clean narrative, as if running a published campaign. Other times you want something more open ended where they can chase down random rabbit holes and see where they go. I genuinely like both, or mixing the two, but everyone needs to be on the same page what the goal as players is or someone is gonna get upset.

I mean, even cohesive epics will usually have player driven deviation, and that's cool, not implying it's a pure one or the other... but there's nothing wrong with a DM wanting to run a "tighter" campaign as long as players are buying into it and are still forging the path there (they're going their own way to Mordor, but they're still going there, in other words).

I really do like both. Sometimes I want Minecraft where I make my own story, other times I want to play out a choose your own adventure... we're going to get to the same destination, but how we get there and what the ending will be is a big question mark.

I definitely agree that as a DM, whether epic or open ended, the paths you haven't thought of that your players throw you is easily the most interesting part on that side of the screen.