People who shouldn't say "Why so serious? Lets put a smile on that face"

I watched The Dark Knight sometime back. Its perhaps the darkest Batman movie ever made in the franchise. Heath Ledger's final act as the Joker was absolutely brilliant. The part when he said line "Why so serious? Lets put a smile on that face" makes me shiver. Now a number of people in my MSN list used that line and put it on their nick.

Now imagine that line by an inappropriate person at an inappropriate moment:

1. Tok mudim to a bunch kids getting ready to be circumcised.
   
   
   
2. Tok Kadi/Priest to the soon-to-be husband and wife.
   
   
   
3. Saying that to mourners at a funeral.
   
   
   
4. Parade commander to the marching contingent at National Day Parade.
   
   
   
5. The doctor who is about to perform a critical operation on a patient.
   
   
   
6. BMT instructor tekanning the recruits.
   
   
   
7. Executioner to a death row convict.
   
   
   
8. Comforting a person on the verge of death.
   
   
   
9. Nurse to a woman who is about to give birth.
   
   
   
10. Customer Service Officer to an angry customer.