New player "What's my AC?"
DM "With felt armor and round shield it would be 7"
Bystander player "MODIFIED BY YOUR DEXTERITY BONUS!!!1"
DM to new player *sighs* "What is your dexterity score again? 10, okay there's no dexterity modifier in your case."
**** later in the game ****
DM to new player "What's your armor class again?"
New Player "It says 7 on my sheet, but I get a dexterity bonus, right?"
DM *glares at Bystander Player*
File under "It happens every damn time" & "Please don't confuse the beginners"