As much as we might love the Humbug, he definitely loves himself more. Sure, he's a fully-developed character and gets a lot of attention for being so funny, but it's probably because he makes it that way. Certainly, he would think it's appropriate that we're spending all this time thinking about and discussing him: after all, he's the Humbug!
This is probably a good time for the reminder that, like all the other characters, the Humbug allegorical – he stands for a particular idea. In this case, he's a (pretty obvious) demonstration of how obnoxious it can be to be too self-absorbed. Think too much about yourself and you might just end up like the Humbug. Don't say we didn't warn you.
What do we know about the Humbug? Well, he's never at a loss for words, that's for sure. It's not until he sees the huge room of gemstones described as trash by the Mathemagician that he's silenced: "for the first time in his life the astonished bug couldn't think of a thing to say" (14.81).
Why is he always chatting? Probably because it's through his words that he is able to project the high and mighty image that he has of himself. Even when he gives praise to other people, he ends up praising himself: "'Splendid effort,' commented the Humbug jovially; 'exactly the way I would have done it myself'" (16.58). That's a sneaky self-compliment if we've ever seen one.
This guy talks the talk, but does he walk the walk? Well, no. Think about the great idea he has for Milo and Tock to go on their adventure, and how proud he is for coming up with this brilliant plan. And then think about his reaction when the king tells him he'll go along for the ride. Come on, Humbug: man up.
Pretty much everything this dude does is for show: he wants to give the impression of thinking very hard and intellectual thoughts whenever it's required, but the narrator tells us that he "was never as happy as when he had a job which required no thinking at all" (17.1). We're onto you, Humbug.
If you remember, the Humbug doesn't join forces with Milo voluntarily, like Tock does. Actually, quite the opposite. And the way we're introduced to his character tells us a lot about him. First, at the word market in Dictionopolis, the Humbug introduces himself with great importance:
"BALDERDASH!" shouted a booming voice. And from around the wagon stepped a large beetlelike insect dressed in a lavish coat, striped pants, checked vest, spats, and a derby hat. "Let me repeat – BALDERDASH!" he shouted again, swinging his cane and clicking his heels in mid-air. (4.39)
Our bug-like friend talks loudly and dresses formally. His whole persona is about getting attention and showing his own grandeur.
But it's when his attitude starts getting our Milo in trouble that we get frustrated with this guy. After the fight which Humbug instigated, the Humbug blames for the whole affair. And what's worse, when Milo gets carted off to jail, the Humbug doesn't do anything to help. No matter how much he redeems himself, we're never going to forget that little detail. Not cool.
Ultimately, though, the Humbug rises to the challenge of going along for the quest – as the guide – and he helps Milo successfully reach the Castle in the Air. He might be a little arrogant, but he gets the job done. And he's hilarious to boot!