I understand that the unflushed toilet scenario is a bit ridiculous (I find it absurd myself) but Crini said other things as well:This would be the first crime in the history of time when someone is killed over not flushing the toilet. Seriously, has this ever been alleged as a motive ever in any Crime?
Young adult women kill over boyfriends or they kill over jealousy usually having something to do with either another girl being popular with the guys or another girl doing better in school. And usually there is evidence of this long simmering jealously. They do not kill over who flushes the toilet, a jealously motive here would be better or at least more believeable (supposing they had evidence of jealousy which they do not)
MK being angry that her peace and time to study were being invaded, after some weeks of smouldering resentment on both sides; the LeChic job rivalry coming on the heels of Meredith having ignored AK on Halloween, etc.
I am not positive Knox was involved, but if she was, I could see how something might have happened, especially if drugs or drinking were involved, and if there were any elements of transference at play (which happens in all sorts of relationships: friendships, love affairs, co-worker relationships, roommate, etc.) In my opinion, Knox would have to be disturbed beneath the surface for something like this to escalate (not entirely normal, in other words, but many people are not for many reasons). Whether this can be proven in court or if the evidence is strong enough remains to be seen. I might have reasonable doubt if on the jury, not sure.
To my thinking, the unflushed toilet MAY have played a part RE Guede, if he felt humiliated at a moment in which he could not bear humiliation.(having harbored amorous feelings toward Ms Kercher, and now feeling like a buffoon as a fight escalated between Knox and Kercher. ) all speculation of course.