I love it when a friend is getting rid of books and lets me go through them before they're sold. I've gotten all sorts of interesting books that way, although it depends on the friend. Some people's books aren't worth looking through. But this friend and her extended family have an interest in politics and things international, and also in literature, so it was a worthwhile afternoon at her house.
And it's always nice to look back on those books after we move and remember where we got them. Buying books at Amazon is lovely, but I like to see the ones I picked up in interesting place. Like Mansfield Park in Amman. And Marco Polo in Bishkek. A Qur'an in Jerusalem. Islamic Art that was a wedding gift from an Arabic-speaking friend. A well-loved copy of Living a Beautiful Life was the first thing my future mother-in-law ever gave me. Most of these books aren't my favorites, but the books themselves are.