Timely as ever, Darius mentions the importance of not referring to "the user" or "the player" in design documentation.
I tell my class to avoid "the user" because it makes it sound like you're writing a piece of software, not a game. Software has users; games have players.
I also tell my class to avoid "the player" even though it's marginally better than "the user." Referring to "the player" depersonalizes the experience and destroys empathy. Darius also pointed out another reason: not all players are identical.
The easy way to do better is to write in the second person: "you press the X button" rather than "the player presses the X button". This builds reader empathy.
The harder way is to create fictional characters, give them names, and tell stories about them. "Confident from his years of experience with Street Fighter 2, Joe mashes the X button into submission." Human brains inherently grok stories, far better than bulleted lists or technical descriptions.
And in spite of all this, half of the design docs I get back in a homework still speak of "the player". The tendency is apparently a tough habit to break. (I remember I had similar problems learning to avoid using passive voice.) But I have to wonder why. Why is it so natural to write in a style that's so unnatural to read? And what can I do, if anything, to really drive the point home... so that students get it right the first time?