***Disclaimer: I have a lot of respect for the many wonderful people I know (and those I don't) that give their all as a school teacher, to make a difference in children's lives. This is in no way an attack on them, but rather a sympathetic understanding of why they are frustrated with the confines of "the system."
Before we ever considered home schooling, I asked a good teacher friend of mine how to choose the best school district to live in for our children. She couldn't really answer that question. What I started to gather from her response was that finding a "good district" wasn't the problem- school was the problem. What she did tell me was that most of her time was spent trying to rein in rebellious children and establish her authority over a classroom, rather then actually teaching anything. She had no real means of discipline, and the students knew it. The administration was very poor and totally unhelpful to her. Much of her time was wasted with pointless paperwork to appease the "system" rather then coming up with new creative lessons for her class. Her biggest pressure was ensuring that her class performed well on standardized tests. The students even used this as a bargaining tool with teachers- threatening to purposefully test poorly so their teachers suffer the consequences.
Did you know that half of new teachers quit in five years? This would have surprised me before I had the conversation described above with my teacher friend. I googled "why teachers quit" received the same basic answers over and over again (scattered among newspaper articles, magazines, and the like):