Why do lady macbeths comments work on Macbeth?

Lady Macbeth's comments work on Macbeth because they play into his own insecurities and ambitions. She knows that he is a powerful man, but she also knows that he is hesitant and afraid. She uses her words to manipulate him, making him feel like he is not enough and that he needs to do more to prove his worth.

For example, when Macbeth is hesitant about killing King Duncan, Lady Macbeth tells him that he is "too full o' the milk of human kindness" and that he needs to "be more cruel." She also tells him that he is "not without ambition, but without the illness should attend it." By saying this, she is suggesting that Macbeth is not ambitious enough and that he needs to be more ruthless if he wants to achieve his goals.

Lady Macbeth's words are effective because they play into Macbeth's own doubts and fears. He knows that she is right, and he is afraid of being seen as weak or cowardly. He also wants to be king, and he is willing to do whatever it takes to achieve that goal.

In the end, Lady Macbeth's comments are successful in convincing Macbeth to murder King Duncan. However, they also have a negative effect on Macbeth's mental state. He becomes paranoid and guilt-ridden, and he eventually goes mad.