-When you walk into Whiterun, you are forced into main quest dialogue
-When you walk into Dragonsreach castle, you're forced into more main quest dialogue and must sit through a scripted conversation before you can even talk to the steward, and you can't talk to the Jarl at all unless you do the main quest
-When you walk into Windhelm's castle, same thing. Ulfric and his right-hand man have a scripted conversation regarding the civil war and you can't talk to them about anything other than joining the rebellion. You can't even buy a house in Windhelm without becoming a Stormcloak.
-There are scripted, expository dialogue scenes in every single town/city and almost every building in the game. These are poor to begin with, and it becomes exhaustive sitting through them every time you make a new character.
-If you choose to play the main quest, you're forced to also join the College and Thieves Guild for reasons that are completely arbitrary.
-You can't enter certain dungeons if they're guild restricted. So for example if you want the dragon shout in Labyrinthian, you have to join the College. And if you want to complete the Forbidden Legend quest, you have to join the College as well.
-You can't buy the Whiterun house without doing the mainquest
-For some reason you can buy a house in Riften, Solitude, or Markarth without becoming a Thane first. Why? I don't see any other thanes in these cities, when was this requirement put into place? Why can't I just walk into a city with a pile of gold and buy the house I want, like in Oblivion?
These are the examples I could think of at the time of writing this. Oblivion and Morrowind do none of this. As terrible as Oblivion's main quest was, I respect the fact that if you never went to Weynon Priory and talked to Jauffre, you would never even hear mention of it, let alone be forced to do it for a certain quest/dungeon/house. Oblivion had an overwhelming sense of freedom. Not only could you do anything you wanted, you could ignore anything you wanted. Not so in Skyrim. This game is designed to funnel you towards questlines, regardless of whether you want to do them or not. It's irrelevant that the questlines are awful to begin with in Skyrim, because even if they were amazing I would still want the option to completely ignore them. I think it's poor design, and it makes the game feel stifling to me.

