PARTNERSHIP AGREEMENTS: Bridge is a partnership game; a team effort. Therefore if you and your partner are on the same level of proficiency, then each of you in a way are responsible for each others misplays and bad bids. Since there is the equation: You = Partner = Team , a mistake by one of you is a mistake by the team. No matter how egregious the error, neither negative criticism nor anger will really enable a person to play better. Instead this will usually cause your partner to tighten up, feel guilty or resent being publically reprimanded. He will then not be in the present for the next hand and make another mistake. More harsh words by you will just keep perpetuating this error/reprimand loop. Compliments and positive reinforcement are the way out of this loop. They are the foundations of good partnerships.
        Often the person making the mistake will realize the error of his ways and how it could have been avoided. If not point out the error quickly, dispassionately and go on to the next hand. If further analysis is required, try to do it after the hand or match is over. Going over mistakes (post mortem's) should not be done during the game in the heat of battle. This type of distraction is bad Bridge etiquette and unfair to your opponents.
       In the monthly ACBL bulletin there is the section It's Your 
Call, in which twenty experts are asked to bid a particular hand. Not all of these experts, and they are world class players, ever totally agree on what is the "correct" bid. That is because there is often no correct bid; it is a position that they take, and can justify. Sometimes the same is true for making a controversial play. You might have to take a particular position that can either work out or be disastrous. As long as you can justify a play or bid, your partner should be understanding no matter what the result. He might disagree about your position, but that is his prerogative. For good partnership harmony you both must agree to disagree.