Language may provide us with the answer to this question.
When someone asks, "what do you do (for work)?", there are two types of responses I have observed (in English).
"I teach", "I practice law", etc is one type. This response provides an action as the answer, rather than an occupation.
The other type of response is, "I'm a teacher", "I'm a lawyer", etc. Here, the person is stating their profession.
I believe that these two responses to the question are quite different, and portray different meanings about the individual to the world. In the former, the focus is on the action, and a strong link between profession and identity may not be present. In the latter, the words "I am" are used to represent the work, the same words used when describing other aspects of one's identity ("I am South African", "I am 23 years old", etc). Perhaps without even realizing it, a large piece of their identity is tied to this response.
My experience in asking this question, at least to people in the United States, is that most responses come back in the form of profession rather than action. What has your experience been? What may the type of response given indicate about values and culture?