Shakespeare always says it best.

All the world's a stage,
And all the men and women merely players;
They have their exits and their entrances,
And one man in his time plays many parts,
His acts being seven ages.
As You Like It Act 2, scene 7, 139–143


















I hold the world but as the world, Gratiano;
A stage where every man must play a part,
And mine a sad one.
Merchant of Venice Act 1