Animal Behaviour

One of the most difficult questions in the world, it seems to me, is how to deal with other people's suckitude.  What do we do if someone we know behaves poorly?  Do we act differently if the behaver is someone we like than we do if the behaver is someone we don't like?  

My friend I.C. and I once discussed the question of how one should behave if one was unfairly or horribly dumped. Should you just let go with the screaming and rage you wanted to scream and rage, or should you behave with dignity?  She told me that she'd once been in a restaurant when a woman had been dumped, and had reacted by becoming enraged and loudly berating her (now ex-)boyfriend for his many bad acts.  I.C. told me that it was plain from what this woman said that the man was a bastard, but still once the woman tromped out you could feel that the sympathy of the restaurant was with him, simply because the woman had embarrassed him by making her huge scene.  I.C.'s moral here was, "Always behave with dignity when being dumped."

Is this also a valid dictum if the issue is not being dumped but rather being faced with poor behaviour not directed at one, but still performed by someone one knows?  If someone I know does something I don't approve of, how do I respond?  Obviously if what the person does has nothing to do with me, or connects to me only randomly (say, I hear they're mean to tramps), I remain silent. But what if someone I know behaves poorly toward someone I like, or love?  Do I still have to treat that person well?  I mean, I know I shouldn't go over and punch them in the head (no matter how much I feel like doing that), but do I have to treat them like we're still all mates together?  Or can I (as I would wish to do) avoid them, or (perhaps better) interact with them with thinly veiled contempt?

Even more knotty is the question of what to do if a friend behaves what I would define as badly, or in a way I feel is wrong.  We take more from our friends than we do from "people we know," and if we're wise we know that friendship is a complex thing that involves a good deal of accommodation, understanding, and acceptance.  But what if a friend does something that we find reprehensible?  We're more likely to find out about our friends' behaviour, since friends tell each other news and confide in each other, but confronting friends is more difficult than confronting strangers:  there is more at stake.  So if a friend tells you they've done something that you think is wrong, what do you do?  Do you say nothing, because friendship involves acceptance and accommodation?  Or do you make your objections known, calmly and coolly, which still risks creating a rift in the friendship?  After all, if my friend behaves badly, what does that have to do with me?  I haven't behaved badly, so what do I care?  I'm not my brother's keeper, right?  But if you do make your objections known, do you make them known, then simply proceed on as if you hadn't said anything?  

A curious one, this.