True friendships are measured by the presence of reciprocity in the relationship, meaning that both individuals consider the other to be a friend. It’s like those well-liked people in the office or on the playground whom everyone considers a friend because they are able to make everyone feel appreciated or welcome. If that popular person is asked to list her friends, however, she may only name a handful of good friends, whereas dozens of others might claim her as a friend. Or think about the less-well-liked people you work with—they may have no colleague who'd “claim” them as a friend, even if they can generate a long list of people they consider friends.