In an interview, Taylor Swift discussed the concept of resilience and one of her best friends, Selena Gomez. Selena just released two singles about her struggles in a relationship. Taylor said, "She is such a revelation because now she is making her best stuff. I'm really excited because when somebody has had great life experience, has had really tough things they've had to go through, and they can process that and make art that's going to help other people... that's what kind of song this is."
She also mentioned she knows who her friends are now because true friends want to hang out when your stock is down.
Sources: 1, 2, 3