Hamlet is a tragedy where there is a part left open, as a part is left open for an improvisational actor in farce. But here the part is left open for a tragedian.
He is fundamentally bored, and for that reason he acts theatrically. The play is written entirely out of spite against actors, and by its nature the role of Hamlet cannot be done by an actor. An actor can act everything except an actor. Hamlet should be played by an actor brought in off the street, and the rest of the characters should be professional actors. The point about Hamlet is that he is an actor and you can’t act yourself. You can only be yourself.
W. H. Auden, Lectures on Shakespeare