Defusing the Dramabomb

Today, I was asked by a colleague/acquaintance whom I'm on good terms with to "pitch in" and help create a "care package" for a mortal enemy of mine (frankly, the only mortal enemy I have), who is going through tough times right now and cannot return to campus yet. Either the colleague is unaware of the enmity I feel towards the stupid cunt in question (which would be surprising, given her propensity for gossiping and melodramatic whining if she perceives somebody doesn't "like" her). However, being the kind and diplomatic soul I am, I managed to "talk nice" without committing anything, even though the vindictive side of me wants to bash the stupid cunt. Sometimes I wonder if being a product of a family of divorce has rendered me conflict-averse, although I am capable of standing up for myself when I need to. I suppose it's only relative. I guess part of being human is the ability to defuse antagonisms preemptively, and whether the short-term costs of arguing are compensated with long-term benefits (be it an improved relationship, or at least self-respect for standing up for yourself). I am not totally sure whether I perceive and weight these costs and benefits properly, although as always, these considerations tend to be context-dependent.