When we're angry about not being heard, we may automatically resort to any number of what Harriet Lerner calls "below-the-belt" tactics. We leap from the facts ("You said you'd clean up the kitchen and I need you to do it") to a damning generalization ("When you say you'll do something, I can never count on you to follow through"). Perhaps we throw a label ("I can't believe how insensitive you are.") along with a diagnosis ("You have a narcissistic personality.") and bring in another party or two to bolster your case ("My therapist thinks that you're passive aggressive, and my sister agrees"). While we're at it, we may slip in an interpretation along the way ("You may think I'm your mother, but I'm not here to serve you like she did") and remind him that he needs therapy. And we serve all of this up in a condescending, mocking, preaching and blaming tone.
Wonder of wonders that our partners don't seem to appreciate our feedback.
Constructive criticism, by contrast, asks for a specific behavioral adjustment that honors your partner's capacity to change. It focuses on actions, not character judgments. The "lightly served" part is especially important if your partner responds poorly to anger or intensity in your voice. People can say very difficult things if they calmly present the facts with no edge in their voice. Or silliness can help enormously as when Mary threatened to charge her husband rent, if he kept putting his clothes on her desk.
A constructive "above the belt" complaint looks like this: You calmly ask him not to leave his things flung around the house, not because he's a big slob (although that may be so) but because neatness is important to you. You "own" the problem ("I'm just not comfortable when you leave your briefcase and coat on the living room couch") and appreciate that there are other women in the world who wouldn't be so bothered by a husband who didn't pick up after himself. You mention the attacks you made earlier, at a time of frustration and you apologize for them....
At a relaxed time, you invite a conversation ("Can we make a rule about where briefcases and coats are kept?" and figure out how to compromise on your different styles. You appreciate that change occurs slowly, in fits and starts, so you praise him for moves in the right direction. After all, you couldn't transform yourself into a person comfortable with clutter overnight. You might even conclude that it would be simpler to sweep through the house twice a day and dump all his belongings on his big armchair until he decides what to do with them.
Basically constructive criticism is expressing your needs in a straight-forward non-judgmental tone and inviting a conversation without bringing blame into it.
After studying thousands of married couples, marriage expert John Gottman concluded that criticism (the nonconstructive below the belt kind) is one of the "four horsemen of the apocalypse," which can clip-clop into the heart of a marriage and can destroy it. This is especially true when criticism becomes contempt, i.e., conveying a tone of "superiority."
For anyone who has this intention, Gottman suggests adding the gibe "What's wrong with you?"