An awful lot of actors shy away from the uglier aspects of the human condition. They want to be liked, which is a cop-out. You've got to go for it.

Mortality defines the human condition.

It was childish to feel disappointed, but childishness comes almost as naturally to a man as to a child.

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.

What you think of others is what you know about yourself

There is a reason the word belonging has a synonym for want at its center; it is the human condition.