90. Learn another language.
As of right now, I know English (obviously), and I have a working knowledge of Spanish. I took three years of classes in high school. I went to France back in 2006 so I did learn a little French. That same year I went to Italy, so I had to learn a few phrases in Italian too.
I would like to learn French and Italian better. However, I would like to learn something different. Much different. I would much rather learn something like Polish or Ukrainian. I haven’t fully decided yet. I think the more languages you know, the more you use your brain. It wouldn’t hurt to know multiple languages either. It would definitely come in handy when I travel the world some day.