But I am very sorry, good Horatio,
That to Laertes I forgot myself;
For, by the image of my cause, I see
The portraiture of his.

– William Shakespeare

Hamlet, Act 5, Scene 2. Hamlet feels guilty over his row with Laertes. He realizes that they are very much alike and sees his own plight in Laertes. Laertes has a just reason for seeking vengence – they are both looking to avenge a father’s death.