"The term Feedback is often used to describe all kinds of comments made after the fact, including advice, praise, and evaluation. But none of these are feedback, strictly speaking." Grant Wiggins
As educators there are two types of impressions we can leave on our students. One is that we leave a positive impression and they remember us fondly as they move through life. The other is a negative impression, and those memories of us are not very fond at all. Both of those impressions can have a powerful impact on our students.
Even in our own formative educational experiences we remember the teachers who failed to say anything kind and those who always had a supportive word. We remember those teachers who challenged us to think deeper and those who wouldn't notice if we were taking a nap in the back of the class.