A friend who defends you when you’re not there has proven more than any birthday post ever could.

What gets said about you in rooms you are not in is the part of your reputation you cannot manage. Somebody standing up for you there costs them something and gains them nothing, because you were never going to find out unless it leaked back. That is loyalty with no audience, which is the only version that proves much. A post is easy by comparison and everybody knows it.

When you hear that somebody defended you, tell them you know. Then do it for someone else and never mention it. Declining to join in is already most of the job.