Describe lennies irrational anger when he does not understand about about the puppy's death

Lennie has the emotional and mental maturity of a five-year old.He inadvertantly smothers his puppy to death. Lennie is more afraid of getting in trouble from George than he is about his puppy's death. Lennie thinks about the consequences of his actions, not tending the rabbits, rather than what he has done to the puppy. He blames the puppy for being too weak rather than himself.