The “Over-Doer” - Just Can’t Say No
When a superior asks you to do a new urgent task:
Remind him/her that you are working on other projects that he/she has already identified as top priorities
Ask for help in deciding where the new task should fall on the list of priorities
Ask "What would you like to give up in order for me to do this?"
Point out that you might be able to do everything, but not to the usual high standards that are expected.