In normal circumstances, if somebody in employment derives some pleasure from carrying out their duties then we would normally applaud this. But there are circumstances when we might, possibly, not be so approving:
a male doctor looking at, or touching, female patients;
a prison officer supervising inmates;
a soldier involved in the occupation of a hostile town;
a teacher administering corporal punishment to schoolchildren.
I imagine that the doubts arise because, although in each case the individual might be carring out his job perfectly correctly, the recipients of his attention are vulnerable. Maybe we think that the individual might be “excessively zealous” in carrying out his duties. (I use the male pronoun here, but — with changes where necessary — the same remarks might apply to a female.)
So what should be done about this?