Be prepared to expect only one moon at night.
You cannot and will not find treasure if you loot the city mausoleum. (Gold coins in every burial urn joke.)
You cannot survive a hundred foot fall into water.
You will succumb to hypothermia if you are outside in winter conditions for too long or if you go swimming in the arctic.
College isn't free and won't teach you to use magic.
You won't experience lag. Ever.
You can't run for hours without end.
You have to eat, sleep, and expel waste sometime.
Cats will not speak to you. Go bother someone else.

Wolves will not attack you on sight.
You cannot kill a bear with your bare hands.
That's all J'derras can come up with now.