telling him that he, too, should be afraid, and if he fears nothing else, Macbeth does fear fear itself.
The witches Oracle stated that he had no need of fear until a man not born of woman challenged him and the Birnam forest moved to Dunsinnae. These are both physical impossibilities. Therefore, it is as good as saying Macbeth need never have fear. So this reading interprets everything Macbeth says to his servant, to Seyton, to the Doctor and about "physique" as the arrogant, confident commanding of a king. So by this reading, Macbeth has no regrets except the one regret that his wife has broken and is mentally deranged
Macbeth is playing the part of a despicable despot, being unpleasant to all those around him. The audience must assume that those that still follow Macbeth do so out of fear rather than loyalty. He is now so arrogant that he considers those around him to be cowards. He refers to his servant as ‘lily livered’, and as for the opposing army he considers them to be lazy and self-indulgent.
When the doctor advises Macbeth that he has been unable to cure his wife of the madness, Macbeth mocks him telling him to throw his medicine to the dogs. The doctor makes the remark that he has noted Macbeth’s own military preparation, and doubts whether it will be a remedy for Scotland’s ills.