Some friends last forever, and some, well, don't. We've all been there at some point, realizing that the dynamic has changed, or that they are no longer the person you became friends with in the beginning. The list of why friendships end are extensive and often specific to the situation, but that does not mean that a few rules of thumb to amicably end a friendship are not universally applicable. But hey, if this so called friend did something notoriously shitty, like steal your boyfriend, post secrets about you online, or call your dog ugly, then you are exempt from remaining cordial. By all means, let hell break loose!