Humor and Verbal Irony

    In a nutshell, verbal irony is when somebody says something that's completely different than what they really mean. It's a tool that lots of satirical writers use, and sometimes it's applied in serious works, but it can also be used in creating humor in a story.
    Sarcasm is possibly the most identifiable and common example. You've got to be really careful when using it in real life (it can seriously hurt people's feelings), but in fiction, in certain scenes, it can be hilarious and endearing. For example: Low, unhappy groans sounded from the other side of the wall. "Dude, are you all right?" Guy #1 asked. "Oh yes," responded Guy #2, "I just love it when old bookshelves decide to dump their contents on me." You can picture the tone of Guy #2's voice, right? And maybe the look on #1's face.
    Another example of funny uses of verbal irony is what I call a "fake" simile. It's when someone says something like "she's about as happy as a cat who just crawled out of a pond." The description is understood in a more illustrated way, and the mental picture it sketches can be more funny. It's not actually amusing when a poor cat gets dumped into a pond, but when picturing the cat's feline glower on the face of an irritated person, isn't it slightly funny?
    Wit. Not exactly sarcasm, but it does usually annoy the person it's directed towards and highly amuse the person watching. It's a little hard to describe, but sometimes it's when a person states the obvious in criticism to the person to whom they're talking, sometimes it's when someone says something "punny" (get it? Puns? Funny? Punny?), and sometimes when someone being witty, they're acting like a smarty-pants. Wit is saying something clever (or obvious but un-thought of) at just the right moment, making the random statement laugh-worthy.
    Exaggeration. Most of the time it holds hands with sarcasm, but it's not uncommon or ineffective to have a "funny character" who tends to un-sarcastically exaggerate most of the time. With an eager or excited tone, a couple enthusiastic bouts of arm waving, and an unintentional rising voice, this kind of character can draw out a couple chuckles. Though exaggerations, in my opinion, aren't quite as strong as its counterpart . . .
    Understatements. These are hilarious moments waiting to happen! The effect is more powerful in a movie or TV show, but they work in novels too when the wording is right. An understatement could fit in fantastically as the final line of a chapter, even opening doors into the next one. Example: "How bad is it, really?" Person 1's eyes turned upward as he thought. "Not terribly bad." (Next chapter) It was terribly bad. It takes a little more build-up and character investment than this example, but there's potential for funniness, right?
    The harbinger sentence. You probably know it well. A little cliché, and whenever it's spoken, you know for sure that something huge and not particularly fortunate for the heroes is going to happen. But when you're writing a humorous story or trying to thread in some humor, it can set a stage. The phrase is also useable for all age-groups because it's something that children, teenagers, and adults would all potentially say. The statement, of course, is: "What could possibly go wrong?"
    Have you ever read a book filed under the "humor" genre? What is it? Is there a particular factor in it (perhaps one of the ones listed above?) that is the chief funniness factor?