In light of my new favorite song "The Letter" by Laurell, and my new favorite time-passing website The Letter Playground, I have just had a new epiphany. I don't have my cellphone on me, so I can't text my sister, so you lucky things are the first to hear this thought from my simple-minded reverie.
Why, when you write someone, is it called a Letter?
...because it is full of LETTERS. Oh my wooord (no pun intended).