The guy at BK was surely having a bad day but that is not an excuse for his behaviour, if he cannot handle it he should not be in a job where customer service is a priority. In Qatar there is a general lac of "Customer Service" for reasons like very low salary and bad living conditions of staff, basically you cannot expect overworked and under paid humans to be happy all the time but then again the choice is entirely theirs so they should do their job as expected and I suggest you should still take this up with the BK management but as it is a franchise you may have to write to their head office maybe not as a complaint but more as a feedback.
The guy at BK was surely having a bad day but that is not an excuse for his behaviour, if he cannot handle it he should not be in a job where customer service is a priority. In Qatar there is a general lac of "Customer Service" for reasons like very low salary and bad living conditions of staff, basically you cannot expect overworked and under paid humans to be happy all the time but then again the choice is entirely theirs so they should do their job as expected and I suggest you should still take this up with the BK management but as it is a franchise you may have to write to their head office maybe not as a complaint but more as a feedback.