Not only because they “teach”, but because they serve as comfort, mentor, encouragement and, fundamentally, light to children to show them the beauty of knowledge and the importance of passing it on. Being a teacher can be hard because you see these kids grow up and go through the year sometimes struggling and hating school because it's hard. All you want is for them to understand the material presented, but you don't know how. You can see their motivation fading as you try every trick in the book and outside the box to get them to understand the lesson, but the light bulb in their brain still doesn't turn on. You study with them and work individually with them until finally, after a lot of time, sweat, tears and long afternoons of study, they get it. It is a revelation of euphoria for them who understand the information and for the teacher, to know that the student finally understands. Personally, having this kind of teacher and seeing their motivation has encouraged me and other students to pursue their knowledge even when it becomes difficult.