Sorry that I have to use English.
Thank you so much for your insightful advice! I cannot agree more---in the future, what I can do is as following :
talk about the plan and timeline with boss in the very beginning;
in teh process of working if there is any difficulty that might cause the delay I will let boss know;
when boss coems over to ask about the progress , do not be panic. It does not simply mean "You should work faster". try to explain to him what has been done and how long I will need further.
