Since I know some Latin (less that 1,000 words), I sometimes have major "duh" moments, when I figure out what a word means.
For example, I was at a gas station that asked me if I wanted to use credit or debit. I always forget the difference between the two, and I was trying to remember which one is which. Then I remembered that "debit" literally means "owe" in Latin, as in "Marcus owes me a pizza"--Marcus debit me pizza.
I still don't know the difference between a credit card and a debit card, but I felt really stupid for not realizing the two words mean "loan" and "owe".
The other day, I was thinking about Aurora Borealis, or the Northern Lights. I spent about a minute trying to translate Aurora Borealis into English, when I suddenly realized that it literally means "northern lights". That was another big "duh" moment for me. Also, I felt dumb for trying to translate something which is already translated.