Using emojis, or speaking in emoji terms, instead of the traditionally spoken English language #urbanhieroglyphics
#urbanhieroglyphics ie. "I heart you" Instead of saying "I love you";
💩 instead of the single word SHIT, and it is just 4 letters, or speaking the words "poop emoji" as a PC term for shit; future people will see the 💩 emoji and say "look at these urban hieroglyphics, they must have worshipped the same shit emperor all around the world. Here is another shit keychain and matching stuffed effigies"
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.