So here's the deal, I like to travel. I like to travel a lot. I found this cool app on Android that let's you tag countries in the world you've visited.
According to the app I've seen 29% of Europe and in general 9% of the world. Not bad considering I'm still in my 20s.

Map of the world - BeenApp

I also always buy an obligatory keyring from each country visit. One with something very specific to the place I visit or something that would remind me of the place. It's not always as easy as it seems. If you don't believe me try finding a keyring with the city of Essen, Germany in a local shop. Eventually I settled for a 'Germany' one instead. Still pretty nice.