Like family and romantic bonds, friendships play a crucial role in our lives. They also constitute the most prevalent type of relationship we experience (Blieszner & Adams, 1992). Some friendships endure for decades, during which the friends involved become family. Others are formed for convenience, such as a friendship with a coworker that you meet with regularly via Skype. While you have a variety of different types of friends, three types stand out as unique, challenging, and significant: best friends, cross-category friends, and workplace friends.