The impact of saying yes to everything you are asked to do can be catastrophic. It can cause undue stress, mistakes and serious time management issues.
How often has somebody poked their head in to ask what is in their mind is a quick question, which in actual fact turns into a major task for you?
In reality situations like these can take you away from more important, more pressing work.
The trick is recognising, and filtering the stuff you can deal with and turning down the things that could mean you not getting home until the small hours.
Obviously you don’t want to become known as the person in the office that says “no” to everything.