I agree with you to an extent. IMO, open world games are boring if there's no sense of character progression or introduction of new gameplay mechanics while you play and advance in the world.

Let's take Infamous and GTA IV as an example. IMO Infamous is less boring as an open world game as your character gains new abilities that change up the gameplay quite a bit. Everything from navigating the world to combat change a fair bit as you go through the game. Sure the things you are told to do remain pretty much the same (go there and clear the bad guys) but how you go about it changes quite a bit. In GTA IV you've got driving and you've got guns... things get really stale. Everything ends up being "Go here. Kill these guys... go to the next story marker for the mission" and the way you kill guys is pretty much always a gun fight where you hide behind cover and shoot when you're clear. New weapons help to an extent but it gets boring a lot quicker.

All the games you listed above with the exceptions of  Infamous and AC tend to suffer from what I described above. After some time even Infamous and AC peak in terms of character depth and get boring quick after they do.

This is why I think Oblivion won me over so much. It's an open world game with a buttload of character depth and play styles. It's also why I think GTA: SA is the best of the GTA series. Your character is ever changing as you play the game (weapon, vehicle skills, physical attributes based on eating, working out, riding bike) and your character takes to your play style. Owning property and doing side stuff for them to benefit you also gives you a sense of developing your character and his surroundings.

I agree that Mafia II and Farcry 2 are horrible sandbox games. Other sandboxes are Jak II, Burnout Paradise, Oblivion, Fallout.

Assassin's Creed 1 and 2 I just don't like, but that doesn't have to do with the sandbox.

The sandbox games Rockstar Games makes are great though and so is Infamous. The first two Harry Potter games were great and so is Batman Arkham Asylum.

I don't really the "sandbox game" is easy to define as there are many different genres using sandboxes and I can't imagine you hate all of them.

It's like RPG elements that weave through all genres.

Maybe you just don't like Rockstar's games

The only open world games that I've fully enjoyed and played to completion are Assassins Creed 1 & 2 and Infamous. Eveyrthing else got boring really fast. Red Dead lasted 3 hours, GTA4 lasted 42 minutes, Just Cause 2 lasted 8 hours and Far Cry 2 only lasted 2 hours. The progression in most sandbox games is horrible and the game play never matches up to the glorious worlds they create. Infamous and Assassins Creed 2 fix those problems.

I find the GTA games good to fool around, running away from the cops, killikg people and stealing cars, but aside of that it is pretty boring.

You are forgetting Burnout Paradise - i coudln't belive how they changed funny enjoyable racer from PS2 times i played on my friends console into pointless driving sandbox.

Also Oblivion and Fallout 3 - those are some of worst offenders here.

So no there's nothing wrong with you there's plenty of people who like story driver games instead of pointless wandering around virtual worlds.