Today at lunch a woman dropped by our table and said our conversation was really interesting, and we invited her to sit down and join us. We made a new friend.
It made me think... when I was very young, many of the friends I made were just people I walked up to (or the reverse) and said "would you like to be my friend?" For whatever reason, this is much harder to do as an adult, though I'm not sure it needs to be.