Ambition is almost never a good thing in Shakespeare. It’s a vice, like gluttony or envy, it seems. The ambitious characters are almost always the ones who fall. Macbeth, Richard the 3rd, Hotspur. And they generally take a lot of people with them on the way down.
The idea of ambition as something to be feared, or to dismiss, or as a shadow with no substance seems like an antidote to an ambition-soaked world. It is 2013 in the United States of America and a person without ambition is generally someone with a problem. As if a person without ambition were just a sad slug, a lay-about who wants nothing more than to lie on the couch and consume. But a culture full of grasping , striving, highly ambitious people doesn’t seem like a pleasant culture to live in. Hang out in a room full of Macbeths and everyone’s bound to get a little anxious.
My own ambition is a fickle creature – one who can energize me and get me moving or who can cut the heart of me, bit by bit, sending me under the covers to hide.
And of course it is a shadow. It does not exist in and of itself. It can only follow you around and changes with the light.