You're not kidding! Also, "full sun" may often be designated without respect for a certain zone. I've bought many plants nurseries stock that say this, then find out they can't take the southern heat!

One of the problems is to get everyone to decide on what each of the terms mean. For example I picked up a plant that was labeled for full sun but right below it were the words that full sun was just 4-6 hours of direct sun not the 14 hours I was looking for.

Another of the problems is seasonal variations. What is dappled in spring may be full sun in fall or dense shade at other times of the year.