i like to play the game as it was intended to be played.
Just a side thought on this.
The basic game comes with, in the Launcher, a menu option for basic mod management (turn them on and off).
The game developers release, for free (and generally at the same time as the game comes out), extensive and robust mod creation and editing tools.
They designed the game, in the first place, to be very modular (unlike some games, where you need to do all sorts of unpacking/hacking/patching to run mods).
Given those things, I'd have to say that (in my eyes, at least) modding is at least somewhat "intended" by the game developers.

-------
Mods... well, there's a huge variety of mods. Yeah, some screw with the game utterly. Some just enhance what's there. Some make interesting changes. Some are hack jobs that just ruin stuff. Like with any creative endeavor, alot of what's made will be junk. But that doesn't mean mods, in general, are bad. It's all up to the modder and the mod user, what it does to the game they're playing.
(Me, I've pretty much always run Oblivion with a level scaling overhaul, because it's nigh-universally acknowledged that Oblivion's scaling is the ur-example of how NOT to do it. And I play with lots of appearance mods - new races, new skin textures, fancy armor & clothes, new hair & eyes. Shorter grass, so you can actually see the landscape in places. :tongue: I've tried gameplay changers like Oblivion XP, to see how it would be like. And I've tried quest mods. Oh, and got to have DaRN UI, to make all the text smaller - I'm not viewing the game on a TV from across the room, I don't need 36 point fonts.

)
I will say that I 99% of the time play a game through first unmodded, so I can see how it is in it's "original" state. That way I can judge better if a mod does something that I might want, or not.