Poisoning

“Do you know what’s important if someone say has poured poison into their victim’s glass?”

“What?”

“That the victim doesn’t notice there’s anything wrong with what they’re drinking. And even if it tastes a little bit off, it’s only enough that they can explain it away and not mind too much, maybe it’s even nicer! - and so it would be too much bother, maybe too rude, to ask for a different glass.”

“And I suppose over time, if there’s only very small doses of whatever poisonous crap is in the glass, if they’re not trying to do it all in one go, the amounts can be built up as the person becomes used to the taste and thinks it’s normal.”