Leave it or Take it

What do you suppose should be done if something is not working for you like for example you have taken up a task, and you are not abe to complete it successfully on multiple trials. Shall you just leave it of shall you keep on trying till it start reaping results ? Its a difficult query because sometimes that task is giving you more sadness of failure than the happiness of hope in tries and other times vice versa. I also feel that at that particular moment of decision of what to do and what not to do, you get more attracted towards the easier path; the difficult part which is the letting go and going on part seems kind of implausible at that time. Being rational is the key here, no matter what ever decision you need to take in life, you need to think hard and clear before going for it. Some times its the heap of emotions that make a decision for you which you might regret later but if the mind and heart both point towards the same direction, just dont think, take a plunge for it ! life will automatically become better ....