|Friends at work can act in unfriendly ways. One reason is that there are friends and there are friends. Some are true friends who would do anything to help each other. However, some are workplace acquaintances, friendly co-workers, or maybe a best friend at work. Understanding the differences can help you understand what happened here.|
A second factor is that the context of friendship at work is unlike most arenas. The workplace is a competitive environment. Your friendly co-worker enjoys talking with you or hanging out at the water cooler with you, but you both have the same boss and may well be seeking the same scarce rewards. When push comes to shove, many friends at work will push and shove to get ahead of you.
You should let your friendly acquaintance know that you were surprised and upset by what he did. He may have an acceptable explanation or even an apology, so be sure to listen to what he says. But no matter how colorful his comments, he has already shown you his true colors.