It's easy to assume that if you get along well with someone, you probably have roughly the same moral code. But sometimes, that's not the case.
Sometimes, friends can unpleasantly surprise you by turning out to be morally lacking. A recent Reddit thread asked, "What was a disturbing sign that your friend might have a broken moral compass?" The answers prove you never really know someone.
She kissed my then-boyfriend during MY birthday party. That was the end for me. She has no respect and I couldn’t trust her any more after that. - Excellent-Elk-1435
She started neglecting her children. I anonymously called CPS twice. They came and never took the kids. 2 years passed, I cut ties and her children are finally in the custody of their grandparents. - PoonGoon8
A few years ago I was out with some friends, there was this guy who started humiliating his girlfriend in front of everyone, did everything he could to destroy her self esteem and brought her to tears. When we were leaving he came to me and said "I felt really good tonight, I really felt like I was in control". And that's how I lost my best friend ladies and gentlemen. - loop_22