On these pages we have often dealt with the emotional ailment called "criticism". Parents to children, husbands to wives, teachers to students, bosses to employees, congregants to rabbis, fans to athletes, citizens to politicians etc. etc. etc. There is a need many have to find something negative and express it. Of course, constuctive criticism is just that - constructive. But, the vast majority of criticism is not constructive but ineffective at best and damaging at worst. People can write letters to the editor day and night, but it is almost never going to change matters.
Very often you have a pattern in marriage. The wife doesn't like certain parts of her husband's personality so she constantly criticizes and harangues him about them. The are married for 5, 10, 20, 40 years and he hasn't changed one iota. He is just fed up with constantly being under attack. All that does is create friction. But yet he wife continues on hoping that maybe THIS attack will do the job and he will finally conform to her standards.
It doesn't work.
Same with parents. They criticize their child again and again, trying to change certain behaviors but it doesn't work. So what do they do? They start criticizing in louder tones, as if the problem was that the child didn't hear them the first time. Or they threaten, as if threats change people. It is hard to people to step out of the box and think of original ways to react and modify behavior.
To criticize someone is often actually a sin called אונאת דברים. It causes the other person anguish and achieves no practical goal. Before criticizing ask yourself if you are criticizing for the benefit of the other person or because of your own needs. The sefarim say that one may only criticize, rebuke and admonish, if he feels love toward the other person. This insures that the criticism is constructive and that there is a chance that it will be accepted. But if the attacked party is not feeling that the words are coming from a place of love and care, he will get defensive [as almost everybody does] and deflect the criticism.
When being criticized, remember, it often says a lot more about the criticizer than you. If he [or she] had an ayin tova, a more positive view on life, were more upbeat, then he wouldn't say and feel what they do.
Of course, one should also seek out criticism from people who have love and a healthy outlook. It can be a great boon to personal growth and positive change. One of the 48 ways to acquire Torah [for reasons you can ponder] is אוהב את התוכחות - loving rebuke.
However, if you are criticizing someone again and again and nothing is changing - drop it. Try something else or come to terms with the fact that they are not changing. Very few people change much for reasons that we may discuss at a future juncture. The only person you can change is yourself. That would be a great focus.