In advertising (as with many professional industries), certain characteristics make a good employee. Dedication and the willingness to put work first are a given. The hours are long, often excruciatingly so. As a result, plans get cancelled. People are left in the lurch at the last minute. It's often impossible to plan anything more than a few days in advance, because you never know when a pitch will present itself, a client will demand a tighter deadline or extra hands will be needed on a last-minute project. Careful planning is a luxury we just don't have.
Being a skilled actor is also helpful. I've sat through countless meetings during which I've wanted to rip my hair out. But the ability to sit, smile and laugh it off is vital. To convince people to believe the emotions portrayed on my face though they often belie my real feelings.