Remember the Mad Hatter from Alice in Wonderland? His hat had a slip of paper reading "10/6" ... and thus, October 6th is now celebrated as Mad Hatter Day. A day similar to April Fools' Day, but more for celebrating/noting silliness.
Silliness of course being the very things our society regards as "normal," but are in actuality completely mad:
--cartoon characters not wearing pants
--working more to afford things you don't need and can't enjoy anyway because you are always working
--why doesn't Tarzan have a beard?
--shoes designed to feel like you are not wearing shoes
--arm rests at movie theaters
--the Easter bunny
--the phrase "head over heels"
The list goes on. Let me know what other strange things we have been socialized to believe are normal!