As a motivational speaker, I love asking audiences about the most rewarding aspects of their work. It's jarring to get audiences whose work is inherently rewarding ( healthcare,social workers, etc) who look at me with a blank stare.
On the surface people say money motivates them but dig deeper and audiences remember scenarios where they made a difference to others.
Usually if it takes awhile to get to the core meaning of the work, I know that the audience is pretty worn down. When you are exhausted and frustrated with your workload, you sense that nobody is keeping score. This lack of appreciation combined with exhaustion can wear away at the meaningful and engaging parts of the work.
It's like being on a treadmill constantly working away but not getting anywhere. A growing sense of dissatisfaction knaws at you until positive emotions give way to disgruntled pessimism.
Audiences like this need more than a motivational speech. They need to get into the habit of regularly appreciating the job, their coworkers and the opportunity to serve others.