You know it's interesting. Back when I took printing in college, newspapers were still using the old linotype machines and headlines and also commercial print jobs were set by hand by loading individual lead cast letters into a hand held wooden or metal rack--and you held it so that you were looking at the words backwards and upside down as you loaded in the letters. We learned to proofread those lines of type quickly and proficiently.
Now 50 years later I can still easily read stuff that's upside down and backwards. See? All of you who think I'm really wierd are affirmed!