Hearkening back to the infamous Alanis Morissette song, "Ironic," it's first most important to recognize that rain on your wedding day isn't ironic. Winning the lottery and then dying the next day is also not ironic. Both are just instances of bad luck.
One reason why irony is often confused with bad luck is because they can be used to describe similar situations—but the words themselves are the difference between simple bad luck and actual ironic turn of events. For example, if you are on your way to an important meeting that could mean a significant job raise but end up being late and therefore not receiving the raise—that's bad luck. However, if the reason you were late is because you were busy bragging about how you're always on time for anything important—that's ironic.
It's easy to get confused about what irony means and how to correctly identify it. Not only are there multiple types of irony, but its use is not meant to be pointed out directly to the reader. In fact, Bob Harris, in his New York Times article, "Isn't It Ironic? Probably Not," quotes the Times' style book with the following:
[The use] of irony and ironically, to mean an incongruous turn of events, is trite. Not every coincidence, curiosity, oddity and paradox is an irony, even loosely. And where irony does exist, sophisticated writing counts on the reader to recognize it.
So, let's take a look at what irony is, the different types of it, and some examples of it used correctly in literature and life.
Verbal irony
When you say one thing and mean another, that is verbal irony. Think of it as the times in which the words you use contradict what is expected. In these cases, there are underlying meanings that contrast with the literal meaning of what you intend to communicate. Most importantly, it takes a certain level of intelligence on behalf of the audience to understand when irony is occurring. As a writer, you can't point out if something is ironic—it must be understood by the audience to have full effect.
Sarcasm, exaggeration/overstatement, and understatement are all types of verbal irony. However, not all verbal irony is sarcastic. Think of sarcasm as having a more biting, derogatory undertone.
Examples
An example of verbal irony can be found in Johnathan Swift's essay, "A Modest Proposal."
[…] whoever could find out a fair, cheap, and easy method of making these children sound, useful members of the commonwealth, would deserve so well of the public as to have his statue set up for a preserver of the nation.
I have been assured by a very knowing American of my acquaintance in London, that a young healthy child well nursed is at a year old a most delicious, nourishing, and wholesome food, whether stewed, roasted, baked, or boiled; and I make no doubt that it will equally serve in a fricassee or a ragout.
Another example would be a character who has been in an awful car wreck and suffered major physical injury being asked how they are feeling, only to respond "I've never felt better!"
Situational irony
Situational irony is when a situation occurs that is ironic. Specifically, it is when something occurs that is incongruous with what is expected to occur. Whereas verbal irony requires a speaker to evoke irony through their words, situational irony can be recognized by a reader without any words spoken.
Situational irony, at its core, shows the differences between reality and expectations, and can be an excellent literary device to hone in on this incongruency. It reinforces the idea that in many ways, control is an illusion.
Examples
One example of situational irony in literature is the plot of "The Gift of the Magi," a short story by O. Henry. The story is of two lovers who are poor but want to buy their beloved a Christmas gift to show the depths of their affection. Della, the young wife, sells her hair to buy a fob chain for her husband's most precious possession—a pocket watch.
However, unknown to Della, her husband, Jim, has sold his pocket watch to buy her a gift—ornamental combs for her long hair. As the gifts are exchanged, the couple realizes that each of their gifts is now useless. Jim no longer has a pocket watch to use with his wife's gift, and Della no longer has long hair that can be put into the ornamental combs Jim bought for her.
Another example is the poem, "Messy Room," by Shel Silverstein. In it, the narrator begins by berating the occupant of a room that has been left in disarray. By the end of the poem, however, the narrator recognizes it as being his own room.
Whosever room this is should be ashamed!
His underwear is hanging on the lamp.
His raincoat is there in the overstuffed chair,
And the chair is becoming quite mucky and damp.
His workbook is wedged in the window,
His sweater's been thrown on the floor.
His scarf and one ski are beneath the TV,
And his pants have been carelessly hung on the door.
His books are all jammed in the closet,
His vest has been left in the hall.
A lizard named Ed is asleep in his bed,
And his smelly old sock has been stuck to the wall.
Whosever room this is should be ashamed!
Donald or Robert or Willie or–
Huh? You say it's mine? Oh, dear,
I knew it looked familiar!
A non-literary example of situational irony would be a party that is planned indoors to avoid being out in the heat of summer. However, on the day of the party, the outdoor temperatures drop to a comfortable 70 degrees with a soft breeze blowing, while the air conditioning on the inside breaks, leaving the party room hot and stuffy with no windows to open.
Dramatic irony
Dramatic irony occurs in fictional or dramatic works and is a device the writer uses to allow the audience to know crucial information that the character does not know. According to Literarydevices.net:
By allowing the audience to know important facts ahead of the leading characters, dramatic irony puts the audience and readers above the characters, and also encourages them to anticipate, hope, and fear the moment when a character would learn the truth behind events and situations of the story.
More often, this irony occurs in tragedies, where readers are led to sympathize with leading characters Thus, this irony emphasizes the fatality of incomplete understanding on honest and innocent people, and demonstrates the painful consequences of misunderstandings.
Example
One of the most famous examples of dramatic irony in fiction is in William Shakespeare's Romeo and Juliet. The moment that Romeo ingests the poison, thinking his beloved Juliet to be dead, the audience knows that Juliet is very much alive. The letter announcing her plans to fake her own death never arrived to Romeo, thus keeping him from knowing the truth while the audience is aware of it.
Another example of Shakespeare's extensive use of dramatic irony occurs in Macbeth, when Duncan announces his trust for Macbeth while being unaware of the witches' prophecy. In that prophecy, which the audience knows, it is revealed that Macbeth will be king and would kill Duncan.
Cosmic irony
While not a part of the more well-known types of irony (verbal, situational, and dramatic), cosmic irony is a type of irony you'll often find in philosophical discussions. It is a subtype of situational irony and is also known as the "Irony of fate." In essence, it is the belief that the fates (or God/gods) enjoy toying with humanity, either for their own amusement or for some greater experiment.
Examples
A literary example of cosmic irony is found in Thomas Hardy's Tess of the d'Urbervilles. In this work, the main character, who is innocent, loses everything to tragedy. Eventually, she dies, and Hardy ends the novel with the words: Justice was done, and the President of the Immortals (in the Aeschylean phrase) had ended his sport with Tess.
Historical irony
Historical irony is when an event occurs that is in juxtaposition to a claim or situation that contradicts it.
Examples
Otto Lilienthal, who created the flying glider, once stated: No one can realize how substantial the air is, until he feels its supporting power beneath him. It inspires confidence at once.
However, the historical irony comes from the fact that Lilienthal was later killed during one of his flying experiments when the air was, in fact, not substantial enough to keep him from falling.
Margaret Thatcher, the first female prime minister of the UK, stated in 1973 that she didn't believe there would be a woman prime minister in her lifetime.
Using irony in your writing
Irony is a fantastic device at any writer's disposal to add a sense of wonder, fate, or even comedy to their story. Using it to juxtapose that which is expected versus reality not only adds depth to your writing but it's also fun for your reader to recognize it when it occurs.