Lois could have thought that there was more to Paul than there ever really was. I have an ex-friend who will swear up and down that she dated my ex-boyfriend. When I asked him about it one time, he said they'd hung out once and he'd paid for the food just to be a nice guy. (I trust his word a LOT more than her word.)
With Sam, Ellen could have fed into her fading relationship with Sam. ("Your father chose his affairs over you girls. He abandoned you.") Or maybe she blamed the divorce for Ellen's alcoholism. Maybe it was years of resentment over his not-so-subtle wish his daughters had been sons.
I agree with Virginia. Perception isn't always indicative of reality.
