No, you don't now what teaching entails unless you do it, this is true for any job. Try it for a year, you'll probably burn out like most teaching fellows. I'm not saying it's harder than any other job it's just more dfifficult than many people realize. At least you acknowledge that some teachers work more than 7 hours a day. Others already described what makes it difficult- motivating kids who don't care, administrators who place impossible demands on their staff, too much parental involvement or sometimes no parental involvement, poor working cconditions and over sized classes. We all acknowledge these but unless you experience it you don't truly understand. As a PE teacher I've never complained even though I always had rough kids and crappy facilities but I am in awe of my colleagues who managed to get so many students to graduate.