Who to write a letter to?

One of my 20 Little Things is to write hand-written letters once a month. I'm not doing so well in this area.

Part of the problem is that I feel honestly like it is weird to write someone you speak with or Facebook with or text with a hand-written letter. It feels very formal. What is there to say if you see my status updates on Facebook? It almost feels like I need some grand reason for writing on paper. Our world is so willy-nilly with communication now, everything is so fast and casual that I am quite stumped at how to find the right tone for a real letter. And the right recipient.

I'd thought about writing to a company or store that I love. But when the time comes, I can't think of one that I want to write to! Is something wrong with me? Can you imagine yourself writing a letter to some store you really loved, just to say you loved it? Why does doing so make me feel like some creep?

The fallback is always Grandma. Grandma writes US letters, and we don't email with her, so it's either that or the phone. She probably wouldn't mind a hand-written letter every month. But I'd like to shake it up.

Who should I write a letter to? Who was the last person you wrote a real letter to? Give me some ideas, pretty pretty please!