Three recent GMing threads from RPGnet: The Big Thread of GMing Tips, GMing is not easy and How much do you personalize the elements of the game?

The second one is the first tip I’d contribute to the first thread. Number three is a very interesting question. Here’s one of the first responses:

I put dozens and dozens of hours into preparing a game they’re going to enjoy. They, on the other hand, just show up.

She’s got a point (read the rest for the context). What do you think?