Dear Amy: I have known “Camilla” for 20 years. She is the closest friend I have, but I know she doesn’t feel the same about me. Instead, she tends to lean on me when her actual closest friend, “Elizabeth,” hurts her in some way. The three of us all work together. Over the last three months, Camilla has leaned on me a lot, confiding in me that she was trying to find a way to extract herself from her friendship with Elizabeth without too much drama. However, two weeks ago, Camilla literally yelled at me — in front of Elizabeth — for no reason other than Camilla had just gotten a bad haircut and I happened to walk into the room as she was telling Elizabeth about it. I was so mortified that I just backed out of the room. It also happened to be Camilla’s birthday.