Failing To Prep Is Prepping To Fail

Daosus' comment in this post reminded me that it's not just failing to read the rules that leads to a player having no fun.

AD&D's Oriental Adventures is an example of the players not bothering to do any of the prep needed to make characters that fit the setting.  Kara Tur isn't the same as Greyhawk and they just treated it like a normal D&D campaign and didn't do any of the social stuff that so enamored me with it.

I had medieval Japan on the brain and even with GURPS (which the players already were fine with) they didn't bother learning fuck-all about being a person living in the Sengoku period with magic.  One even took my copy of GURPS: Japan home for a week and didn't even take it out of his bag.

WW2 at least has movies they likely have seen for them to base their characters around.

Traveller is a world with near 50 years of material and a new player will have to take sips from the firehose or they will not even know what they don't know and there's just too much to do on the fly now for the GM.

Something that's important about this lack of preparation is the player's character is, nearly always, FROM the world setting!  They are members of their home culture which isn't a late 20th, early 21st century American.

The players who read the material get back more than they put in.

The players who didn't are always either bored or upset that they aren't getting what they wanted.