Oh for pity's sake Suzie, you will find that some people act unprofessionally in all fields. The only reason teachers get it in the neck so much is because everyone comes into contact with them at some point in their lives, therefore they (you?) feel qualified to judge all teachers.
I can't think of another job where you are expected to put up with daily harassment, the threat of physical violence and extremes of behaviour, as well as play the role of teacher, office worker, guidance counsellor, babysitter, security guard, mentor, mediator and still be paid the same as an unqualified PA. OK, some teachers don't take their role seriously enough, but most, especially in secondary schools, put up with a lot for their salary.
The main problem with teaching in general, in my view, is that it has been devalued as a profession over the years. An indication of this is the low pay. Teachers no longer have the support of parents nor the incentive to pour their hearts into their jobs. Perhaps if people started to value this incredibly stressful job more, children would follow suit, and achievement would be higher overall.