The context of the following conversation is Kendall and Skylar had been good friends for a long time, Kendall always had Skylar's back.:
Kendall says Remember Skylar, the girl who works with me? She back-stabbed me today, claimed my ideas for the new sales campaign were hers..
The friend responds Oh no..
Kendall responds Yeah, and it could cost me a promotion.  Trust me, I'll document every communication I have with her from now on..
The friend responds That's a smart strategy.  I'm sorry she betrayed your trust..
Kendall responds That's what saddens me so. We were good friends for so long..
The friend responds You're the best, Kendall, but sometimes people change their ways when we least expect it..