Originally Posted By: tsuwm
10 Eastern, 9 central, and (by implication) 10 Pacific.

... which always left us on Mountain time to do the arithmetic (simple though it is). In my experience, people who've lived mostly on the West Coast are somewhat less likely to have a grasp on time zones due to having their TV programs come on at a time sometimes announced as "Eastern and Pacific".
A site announced Monday that something was happening at "7:00 AM Eastern (GMT - 5)" which caused a huge argument on their forums afterwards. The East coast is currently in Eastern Daylight Time which is UTC - 4 so anyone figuring it as GMT - 5 was wrong, but that wasn't the only way that people mis-understood it.