The affirmation of students is absolutely necessary and there are many reasons for this. First, it is important for the student to see him- or herself in a positive light. Students also come to class with a great many worries—either because of problems at home or problems with friends, bullies, etc. Positive interactions at school may be the most important and brightest part of a student's life. Affirmation allows students not only to trust in themselves, but also in trusting others. It gives a young person the opportunity to believe in what they can accomplish because someone has provided that youngster with validation. Can a person receive too much? Absolutely not. In school, children cannot imagine what they can be and do in the future—unless someone takes the time to praise their strengths and show compassion, understanding and a way to overcome obstacles, difficulties and shortcomings.
If a student is angry or uncooperative, causing disruptions, and/or dysfunctional, there is a good reason. A one-on-one discussion might be advantageous to the student. If a counselor is able to provide the teacher with background on the student's problem, it makes it easier to understand the student's circumstances. I don't believe a teachers should lie to a student, but find something that is worthy of praise: talents, a sense of humor, an ability to speak respectfully when calmly addressed. Acknowledging his or her value as a person, regardless of how aggravating or disruptive he/she may be is not wasted, as long as it is a sincere expression. Will he receive your comments gracefully, not necessarily, but they are no less necessary. I agree with others that praising anger is not something I would do: to survive in the world, a person needs to come to terms with anger and express it outside of the classroom: in therapy if needed. One can say something like, "I appreciate your frustration and understand that it can sometimes be tough to express yourself without anger, but it is important to find positive ways to handle your anger." Refer the youngster to guidance.
Affirm, affirm affirm!!!