Do GPs treat and prescribe for themselves? If they saw another doctor for treatment, would they reveal their own job as a doctor, and how would this affect the treatment they received?
Hairdressers: I imagine you can't cut your own hair, but are you very critical of others doing your hair?
Teachers: if you have kids, do you reveal your jobs when you go to parent evenings? Are you more critical or supportive of teachers than the average parent?