Without fail, his superior will get angry and impatient even before he finishes speaking, "If there are problems, get them solved! Whatever it is, get it done by next Monday!"
My colleage would accept the task grimly, but complain incessantly about it. However, he will work hard to finish the task and always completes his task within the designated deadline.
Although he never failed to meet the deadline, his boss was displeased with his pessimism. At the year-end review, he failed to reap what he sowed and complained about the injustice of it.
I told him, "In your superior's opinion, completing a designated task is your duty. You will not be given additional bonus for that. However, if you adopt a pessimistic attitude, he will deduct points for your poor attitude. No matter what duties you are given by your superior, you must be prepared to complete it. Since this is the case, why not adopt an optimistic attitude and accept it readily?"
Superiors never like hearing things like 'I can't do it' or 'It is very difficult'. Even if it is true, they do not like to be 'warned' about it by their employees, as it only implies that their employees think they are stupid and do not understand the difficulty of it.
If you use a warning tone to reject your superior's proposal, he may feel embarassed and provoked to use his power to force the task on you instead. Work has to be done, so unless your superior is a very compassionate and broad-minded person, do not attempt to defy him under such circumstances.
I hope you have learnt something useful from this!


