Even something as simple as a single word can give away absurd amounts of information about us.

I used to be ashamed of my nationality and actively tried to hide it. I was very successful at it too, never had a single person identify me... Until I tried playing an MMORPG I used to play when I was a kid and was still learning English. Long story short, I misspelled the name of an item because of my childhood memories. Turns out that mistake was very specific to people of my country.