In Shakespeare's Hamlet, the main character's tragic flaw is his over-analysis or over-thinking of everything. One of the most telling events is when Hamlet has the opportunity to kill Claudius in Act III while he is praying. One of the reasons for Hamlet's hesitation up to this point was that he wanted to make sure that the ghost that commanded him to revenge his father's death was not a demon sent to damn his soul. "The spirit that I have seen may be a devil" (II, 2, 579-580). Hamlet's manipulation of the play, "The Mousetrap," was intended to confirm or deny Claudius' guilt. "I'll have grounds more relative than this. The play's the thing wherein I'll catch the conscience of the king" (II, 2, 584-586). In the moments after the play, he tells us he could "drink hot blood," as testament of his newly realized ability to commit murder (III, 2, 365).
However, when he comes upon Claudius, apparently praying (he is actually struggling to pray, as Claudius' soliloquy informs us), Hamlet hesitates because he over thinks the consequences. He convinces himself that instead of revenging his father's death he will be sending Claudius directly to heaven. "O, this is hire and salary, not revenge" (III, iii, 82).
This over-thinking hesitation is made abundantly clear when compared with the actions of Laertes. Laertes, the obvious character foil for Hamlet, has also had a father killed and experiences no such reservations to action. He is so eager and willing to act that he allows himself to be manipulated by Claudius.