Truth. I had a rather messy falling out with a group of friends once. I won't bore you with the story but I have seen that type of thing first hand and it doesn't leave a good taste in your mouth (worse than a break-up in a lot of ways because you expect them to leave at some point).

I have spent time thinking about why certain things seem to be harder on us than others and I think it is an abuse of trust that really hurts people. This applies to some of our worst crimes (child abuse and such) and the reason "snitching" gets people shot. In that sense it is more universal than the most basic laws because even the murders and thieves know it is wrong. That could just be the years I spent as a psychonaut talking though lol.