Because seriously, the importance of the teacher's role in society has to be understood--never taken lightly or for granted.
Think about it--a child who has completed a career in primary and secondary education at the very least has, on average, spent 7 to 8 hours per day, 5 days per week, and 9 months per year in school, for an average of 12 to 13 years. For these time periods, children are completely out of sight and care of their biological parents. Parents actually see and hear nothing of what their children say and do till afterwards--of who they encourage or abuse, how often and sincerely they participate in activities and responsibilities, or how effectively they actually develop into functional, contributing, unique members of society.
For these periods of time, mothers and fathers effectively give up the roles of mentor and parent, and pass them on—though they may not know it or may deny it—to their children’s teachers. These individuals, many of whom the children and parents barely know, are entrusted with nearly all the responsibilities of a parent, in addition to much graver consequences in terms of error or failure. So much rides on the effectiveness and the dedication of these people in the lives of a nation's children. In my opinion, it kinda makes you wonder how grown men playing games on TV make more money than the people who quite literally shape and guide the learning ability of the next generation.
Teachers have an impossible task, honestly. While the world and everyone in it can insist that there will always be rules and set regulations to refer to and fall back on in life, the reverse is so often true. Life is anything but some standardized test that can be crammed for. It's so much more like an ever-changing mass of decisions and responsibilities, cloaked in the illusion of the routine and the mundane. It becomes the teacher's duty to train students to constantly adapt to new situations, to integrate and appreciate past experiences, applying them into new scenarios. Because of that, the teacher must be equipped to ensure that students of every race, culture, ethnicity, gender, sexuality, ability and/or disability have a fighting chance to make it as individuals in society. The good teacher needs to know the world so the student can be shown the world.
At least, that's how it should be. in a perfect world, every teacher would be this dedicated. i don't need to tell you that this isn't that world, by any stretch of the imagination. So when you do meet a teacher that still has that idyllic gleam in their eyes about what teachers should and can be, and how they can and should change the lives of students for the better--work with them, ok? Cut them some slack and help make their jobs easier. They're carrying the weight of the next generation on their underpaid shoulders, and smiling all the way for it.