When someone interacts with your game, they will quickly form an opinion of what sort of actions are required from them. This initial impression needs to be accurate.
For an example of this done well- when I start to play Mario64, the first thing I do in the game is skip a dialogue box. The next thing I do is run, jump, slide and bounce. And for the next 40 hours of gameplay, give or take, I keep doing those things. Maybe I'll learn to time my jumps better, or bounce with more presision. Maybe I'll practice running in circles more at some points of the game. But what you see is what you get.
Here's a similar game that failed this task - Super Mario Sunshine. This game starts terribly. Lots and lots of cutscenes, and then you are finally tasked with cleaning grafitti off the ground with a water pack. Then there is a chase (more cutscenes) and finaly you are put into what I recognize as a Mario64-style level.
But in this level there are no cutscenes, no grafitti to clean, and no chase sequence. What you have instead is classic running, jumping, and sliding. Since I'm an afficianado, I was able to forget the torturous initial hour, and start playing the game I meant to play all along. (I really like Super Mario Sunshine) But the game did not start well. It did not do a good job of showing up front what the experience was all about.
I understand why the game went wrong - all that exposition up front was meant to contextualize the action that followed. They wanted to explain the existance of the water pack, why you had it, why you were chasing after Peach, what this island was all about, and so forth. But the problem is - I didn't need to know that. What I needed to know, at a very basic level, was what my relationship with the game was going to be. I needed to know what I would be performing in the game.
The place that designers go wrong, I suppose, is that they concern themselves with a particular experience in mind, rather than a specific gameplay idea. An "experience" in non-interactive. Movies and television have taught us about enjoyable experiences. Some games pride themselves on their non-interactive elements. But a really excellent game needs to rely on it's gameplay. That game is driven by a specific idea that needs to be passed to the player quickly.
When players talk about games, they talk about the experience. We have lots of language for discussing experience, but relatively little language for discussing gameplay. But as designers we need to look beyond those shortcomings and create something that will be compelling enough to allow players to have an experience on their own terms - not on ours.