After a few decades of failing as a mother a woman can begin failing as a mother-in-law. It’s not that she’s doing such a bad job — it’s just that her children (and later on their spouses) — are never satisfied.
“My mother is critical.” “My mother is needy.” “My mother is distant.” In other words “My mother is a flawed human being and I don’t like it. I want her to be perfect: an all-knowing all-giving all-loving rock of support.”
Unfortunately although most mothers are nice people who love their kids plenty every single one of them is imperfect. Women who are mothers know that their kids have complaints about them and they tend to feel guilty and awful about their inadequacies. Like everyone else they too think that mothers are supposed to be perfect. (How come no one expects this of fathers?)
A new concept was invented to help mothers live with themselves and their quirks: “the good-enough mother.” This concept relieves moms of having to achieve the impossible goal of perfection and allows them to be just human. As long as they aren’t cruel irrational or otherwise disturbed mothers now have permission (from each other and from psychologists) to have a bad day here and there to say the wrong thing on occasion and to completely mess up sometimes. Mothers-in-law may not be as lucky.

A Different Ratio
Mothers-in-law it seems cannot afford a slipup. Consider the rules of intra-familial communication: From parent to child the ratio of good-feeling communication to not-so-good-feeling communication is 80:20. In other words 8 out of 10 sentences from a parent need to feel good to the child. Smiles compliments and acts of kindness feel good; criticism disapproval and discipline feel bad.
For teenagers this ratio becomes 90:10 because adolescents have even less tolerance for negative feedback than younger children do. When it comes to married couples the ideal ratio is even higher: 95:5. (How many “not-good-feeling” communications do you want from your spouse each day? I bet you’d like the 100:0 rule!)
The ratio of parent-in-law to child-in-law is higher still: 105:-5 meaning that one must give one’s in-law child more good-feeling communications than exist in the universe and give him or her less than zero bad-feeling communications.

Zero Disapproval
Now here’s where things most often seems to go wrong: in the tiny remarks. The tiny (negative) remarks and the equally tiny (negative) facial expressions can do decades of damage to the in-law relationship. This is especially true if these tiny disapprovals occur at any of these junctures:
•the first meeting
•during the engagement period
•during the wedding celebrations
•during sheva brachos
•during the first year
•six months before and after a child is born
•at any other time
And I’m only partially joking. Negativity of any type and size tends to harm any relationship. The effects are somewhat more intense in the mother-in-law/child-in-law relationship but the principles are the same. Criticism judgment unsolicited advice or disapproval — no matter how subtly conveyed — can have destructive consequences.
It’s up to the mother-in-law to know and apply this information. Decades more mature and wiser the mother-in-law is the one to take the lead in this relationship. She has already raised children and knows how important encouragement acceptance and affection are in fostering a healthy relationship. She knows too that the newcomer to the family is not yet able to decipher the family code to understand that a “helpful remark” is just that or that a comment said in humor is meant to be funny!
The mother-in-law is more cautious at first giving the child-in-law plenty of time to find his or her way and giving the relationship the time and space it needs to develop.
So who is the “good-enough mother-in-law”? She is a woman who affirms her own child’s marriage by warmly accepting the child’s spouse. Unlike the good-enough mother this woman can never safely lapse into negative communication. But this should be fairly easy because unlike a mother a mother-in-law has no mandate to teach her child’s spouse. Unless there are unusual circumstances she can just relax and let the child-in-law be him or herself. Indeed if she is just kind thoughtful and helpful in those brief hours that spends with her child-in-law she’ll be a good-enough mother-in-law.