FRIENDSHIP POLL: DEUCE-CHUNKERY

I have a question to pose.
What is that irreversable action (or actions) that makes you realize you need to dead a friendship?
For me, this happens when said party does something that psychically, spiritually or ethically revolts me, i.e. narcotic drug addiction (sometimes), megalomania (usually), extreme-right social views (unless they are blood relations), and/or rawdog cheating (ew). I am really good at not being friends with people who transgress my probably-too-lenient boundaries. What about power-addiction? Major friendship-interfering vice and gluttony? Narcissism? Instances of disrespect piled one by one like so many princess-pea-mattresses? When do you cash it in and cut the leash?
Question B: Would you stop being friends with a someone who cornily chunked deuces and/or “ironic gang signs” in all their myspace photos?