Macbeth's death in his fight against MacDuff, and the partial redemption for his evil that came from dying in a fair fight rather than killing by proxy, always struck This Troper as being a powerful moment, but I could never quite see why it got to me so much. Then I realised: it was totally foreshadowed at the start of the play, when the thanes execute the traitorous former Thane of Cawdor and comment that "Nothing in his life/Became him like the leaving it". The two Cawdors both acted against their countrymen, eventually dying for their deeds but redeeming themselves in their last moments. Wow.
I once heard a short lecture about Macbeth that took me from thinking it was just okay to thinking it was megabrilliant. The lecture hinged on the Lady Macbeth line when she says, "I have given suck and know how tender 'tis to love the babe that milks me." It's kind of a throwaway line, since she changes the subject pretty quickly, but wait a minute - when? When has she given suck? This play is all about succession - if the Macbeths had kids, we'd definitely know about it, and they don't. The only explanation is that she must have had a child who died. And suddenly this play is about being a dead end- sure, Macbeth is winning the kingdom, but winning it for who? There's nobody for him to give it to when he dies, which makes the whole thing terribly pointless. And once you start looking, dead babies are EVERYWHERE in the play- Lady Macbeth talking about smashing a baby's skull and trading her breastmilk for gall, MacDuff's kids getting murdered, the dead baby finger in the witches' brew, the two dead babies that appear in one of Macbeth's visions (one wearing a CROWN, forcryingoutloud)... and there's more. And then who kills Macbeth? MacDuff, who was from his mother's womb untimely ripped, of course, the antithesis of dead babiness.
Actually, there is a perfectly straightforward explanation for this; while it is true that Macbeth (reigned 1040-1057) was childless, Queen Gruoch had a son, Lulach, by her first husband, Gille Coemgáin. When Macbeth was killed in battle in 1057, Lulach briefly succeeded him as King of Scotland before being killed in battle in 1058. It has been suggested that the references are evidence that Lulach was included in earlier drafts of the play.
MacDuff actually at one point says directly of MacBeth that "He has no children". I also noticed the apparent contradiction when Lady MacBeth says she has 'given suck', and came to the conclusion that she'd either had a child by someone other than Macbeth [yes, she did - check out Holinshed (Maven)], or - more probably - they had had a child who had died. Which, as you say, just adds a whole new layer to the play.
They built on this layer for a production that I saw in Stratford in 2011. The witches were not crones, but children, and they used dolls to explain the prophesy and the apparitions. Later, though, those exact same children with those exact same toys were MacDuff's children (and they were just as creepy). They emphasized all the mentions of children in the production.
The bit about Lady MacBeth not being able to kill King Duncan because he looked so much like her father. Shakespeare probably didn't mention it because his audience would have known that Lady MacBeth and Duncan were first cousins; her father was Duncan's father's younger brother. (Which explains why MacBeth was able to take the throne; he was a Royal In Law already, AND a war hero.)
Moreover, MacBeth was Royal kin on his own account - he and Duncan were first cousins, as their mothers were both daughters of Malcolm II (who had no sons). Maven
This troper recently realized that the forms of the apparitions in Macbeth represent parts of the prophecy. The helmeted head that says to "beware Macduff" is Macbeth's severed head, which was severed by Macduff. The bloody child that says that "No Man of Woman Born" can kill Macbeth is bloody because it represents a child born by C-section. Macduff was born by C-section. Finally, there is the man who holds the tree branch and says that Macbeth cannot be defeated until Birnam Forest marches against him. He holds a tree branch because the soldiers who storm the castle at the end of the play use tree branches to hide their movements -Marky Mark
In Macbeth, Shakespeare breaks many standard writing tools. The main character is very unlikable, as is his wife, and the climax of the story is at the beginning. Despite this, the play is still amazing and one of Shakespeare's best known works. On top of this, since the majority of the story takes place after the climax, that drives in the theme that this is a story about how Macbeth falls from his highest point. There's some symbolism for you. -Froggy
Macbeth is widely known as a tragedy; however, if you think about it, it's not. What was Shakespeare trying to evoke from the audience? It wasn't anger, humor, or heartwarming - it was terror. Shakespeare wrote the first horror story to ever be performed.