This fear of having to see the world through someone else's eyes goes a long way to explaining why it is that the Pattersons do so many foolish, reckless things. Take this trip they're on. John and Elly clearly seem to have spent the last year looking forward to doing something they can see to be useful and are baffled that the children might want to relax instead of being woken up at an early hour and spending a month doing confusing, back-breaking and dirty work while being sneered at and called stupid by a snotty, sneering little cousin who needs a kick in the teeth for being a little bitch who can't or won't wrap her head around the fact that city kids might not want to do farm work. Simply put, the parents' belief that working on a farm is a pleasant change of pace combined with their refusal to see things the way their children do blinds them to the fact that being packed off to a farm to do backbreaking work wherein the only 'reward' is having to absorb verbal abuse and mushhead pieties from a lantern-jawed country mouse cousin is as effective a way of teaching children how valuable it is to work for a living as Greg Wilkins's constant bitching about how cruel and unfair it is to be gainfully employed.
This not wanting to see the other person's point of view is also why John feels betrayed when Elly calls him out on being an insensitive ass. In his mind, since his feelings aren't the ones being hurt when he implies that she's lazy, his being told to shut his ugly, hate-filled mouth if he refuses to behave like a human being instead of the larruping arsewipe he is is being told that he can't speak his mind.
It's also why he's proud of Mike for being an insensitive dick to anyone who isn't him. In his twisted, selfish mind, Michael isn't a loutish oaf lashing out at innocents because he feels stifled, he's a free spirit who isn't being held down by some sort of conspiracy of women to silence and emasculate men. A man with common sense would know to shut his mouth and when to tell others to do the same. John doesn't want common sense because it might expose him to an admission of error. Given that he's still Johnny Jump-up who thinks that he'll be teased by scruffy eight year olds if he cops to screwing up, an admission of guilt is something he won't make. It'd be like laughing at himself and other things that would rob him of his 'dignity'.
We see a similar process when Elly refuses to see that her children do not see her as the conflicted, confused parent we know her to be. Since it would kill her to admit that she doesn't actually know what she's doing to the children she isn't raising very well, Mike ends up with the mistaken impression that Elly enjoys lecturing and arbitrary punishments. Were she to say that she feels overwhelmed, she'd appear weak and that can't happen so he still thinks that Elly likes to yell.