I've had the worst year or so of my life at work and even now it's supposedly over my reputation has been tarnished because people I barely know have heard and believed stuff about me because I was advised and believed that it would look bad if I spoke about what was happening to people who weren't themselves directly involved. Now one version of events had been spread and not countered and it's too late for me to do anything about it.
I think similar things have happened many times in my life with the same outcome, but this has been the most impactful.