This is not a question about academics such as myself. We're a different kettle of fish, as stuff happening outside the classroom, in particular scholarly and other writing, is so central to our career choice.
Rather, I'm ruminating here about K through 12 teachers, only slicing off the upper and lower ends. Those who work with very young children are also a distinctive group, while high school teachers remain as yet outside my experience as a parent.
For those who remain in the grouping, I have noticed three basic types. The first are the people who actually want to be teachers. Motivations may vary, but sometimes I discern a sense of "I'm going to be the sort of person I wish had been there for me, but wasn't." Obviously, this is the type one wants one's children to have. There are plenty of them, but they are unfortunately not as common as one would like - certainly below 50 percent, in my experience as a parent.
Those in Type 2 want a white-collar job, no hard physical labor, that sounds good when you tell people you're doing it. And they want something that doesn't take too much hard-core professional training, and that doesn't require specialized skills of a kind that are too easy to test for objectively. Their chief goal professionally is advancement with as little challenge and trouble as possible.
Type 3 wants inferiors, in size, age, and knowledge, from whom to demand admiration. This type is potentially even worse than Type 2.
Needless to say, Types 2 and 3 attempt to masquerade as Type 1. The best diagnostic I know is that Types 2 and 3 are generally humorless.