In volunteering to take on extra responsibilities when it's not going to be rewarded in terms of pay/promotions?
Having joined the Civil Service from private practice I'm struggling to get my head around this - in industry you obviously want to be well thought of when your boss is looking at bonuses/promotions, but that isn't a factor here when you've got to go through an interview panel with colleagues you don't know everytime you want to change role (and no chance of any bonus above a £20 gift voucher 😆).
Things like mentoring juniors, running training sessions, testing new programmes etc that are outside of your job role and add to your daily workload.
Do people do it because they need the competency experience? Or just for the greater good of the department?
I generally just want to go in, do my work and keep my head down, but don't want to look unprofessional.