In Act 3 ,Scene 1, Hamlet has the debate every man & woman must have with themselves whenever they experience or come into contact with injustice ...

“To be, or not to be ???????
That is the question: Whether ’tis nobler in the mind to suffer the slings and arrows of outrageous fortune ….... “…....’Tis a consummation ........ Devoutly to be wish’d........ To die, to sleep — To sleep – perchance to dream ....... ayyyy, there’s the rub .......For in that sleep of death what dreams may come ???????
When we have shuffled off this mortal coil…....”

Hamlet is haunted. His sense of justice , honor ,& loyalty are the recipe for his madness. He is at a crossroads where he may be able to stake out a fairly comfortable life if he falls in line & is able to shake off a few assasination attempts. This option offends his honor & leads him to contemplate suicide to escape his predicament, leaving the whole sickening affair to the debauched & corrupted court to wallow in. Alas, he imagines the possibility of that slumber in oblivion being interrupted by dreams. Dreams haunted by "murder most foul". Righteous vengeance, justice, & honor squandered for eternity with no recourse.
He takes the only option a man of honor can take. He sets about to extract justice from those that wronged his family , his people ,& himself...