The friend who notices what changed has paid attention beyond the version of you they first knew.

Most people file you under an early impression and stop updating. They respond to the person you were when you met, which is comfortable and slowly becomes inaccurate, and it can be lonely to be known mainly as a former self. A friend who spots that your opinions have moved, or that you handled something differently this time, has been watching the current person rather than consulting an old file.

Say out loud when you notice a change in someone, without judgment attached. And when a friend notices yours, treat it as the compliment it is rather than deflecting.