My mom used to be very persnickety about thank you notes. Every year, my brother, sisters and I wrote to thank our aunts for sending us holiday trinkets, and we thanked grandparents for enclosing treats in our birthday cards. Though we often grumbled at having to execute this task, as adults, we see the point.
I confess I still write thank you notes to people who do kind things for me. And when I read something that blows me away, or if I see some amazing art installation, or hear music that takes me somewhere unexpected, I feel drawn to scratch out some sort of thank you note to each artist-- usually in the form of an email. Most people write me back quickly, and thank me for taking the time to say those few words.
Maybe you'd consider writing to thank someone for something they created, or a kind gesture they offered you? You won't just surprise them with your old-fashioned note. You'll brighten their day.