Lack of parental support on the whole, impossible targets, forever changing goalposts put in place by over-privileged idiots who have never even attended a non-fee paying school in their life, inspections by people with agendas, lack of respect from most sections of society, horrific hours, shocking pay when it's calculated on an hourly basis and compared to other professionals, disgusting working conditions eg not being able to have breaks including toilet breaks, hands tied by red tape when it comes to disciplining pupils, bullying by incompetent heads, under constant scrutiny both professionally and personally, under attack daily from people who know absolutely nothing about what the job entails, having departmental budgets constantly cut so you are struggling for resources, having to pick up the pieces when schools increasingly employ non-qualified staff to teach classes instead of qualified teachers, threats from aggressive parents, having to increasingly do the job of a parent as well as teach pupils....
Who would NOT want to be a teacher? No wonder it's attracting people in droves and the retention figures for the profession are at their highest!