Teachers are one of the most important people in a child's life. They grow up learning from these adults and they feed off of how these higher authorities treat others and themselves. As a child we want to make people happy with what we do. There is nothing better than seeing a smile on a face and knowing it's from you. Although, there are a ton of great educators out there I'm sure we all know there are a ton of not so great ones too.
A teacher should support a student in whatever their endeavors are. They shouldn't degrade their students and almost make fun of what they are turning in or what they are doing. As a performance based student I have heard "oh, you're a dance major... what do you plan on doing with that?" or "well don't stress if you don't understand this I know you're a dance major." Hearing that is so degrading because you're blowing off our major and more importantly our passion. We don't criticize you for only knowing academics and not being able to keep rhythm to save your life.
Another reason it is important is because if a student is constantly hearing the negative or nothing at all they get discouraged because nothing is ever good enough. A teacher needs to be able to see the good and the bad in all things and be able to cushion the bad while still remind students of the good. As much as you don't want someone to get cocky or show favoritism you need to acknowledge that a student does well. They might never be perfect but there is something good in everything.
Sometimes a teacher can be the deciding factor for college majors, careers, and goals and if a student has a bad experience with someone they look up to it may alter what they think of themselves or hat they plan on doing. So for all my teachers out there thank you for being as supoortive as possible and helping me get to where I am right now because I can't imagine being anywhere else.