Irony. I couldn't start out with any other word, really. Perhaps if Alanis Morrisette had bothered to master a word a day she would have realized a black fly in her Chardonnay was no more ironic than rain on her wedding day. She could have named her anthem, "Isn't it Ironic", something far more appropriate like "Isn't it a bummer...", or "Doesn't it really suck...". Irony is a tricky thing to define, I'll give her that. It's so tricky, in fact, there are an astounding number of slight variations from one definition to the next.
Remember the line from the early nineties movie, "Reality Bites", when a potential employer asks Winona Ryder's character to define irony and she can't. She says, "but I know it when I see it!". I don't think that's too far off for a lot of people. Not for you though, or if it was, not anymore. There are basically three types of irony; Verbal, Dramatic, and Situational.
Verbal Irony is the disparity between what is said and what is meant. The words used convey a meaning that is opposite to its literal meaning. Sounds like sarcasm, right? The two are so similar the terms are mistakenly used interchangeably. Irony, however, is more subtle than sarcasm. Boiled down to bare bones, you could say that sarcasm is like irony, only meaner. Sarcasm is manifested chiefly by vocal inflection in the spoken word, while irony is shown more by the arrangement of words. Clear as mud? (That's an ironic simile, btw.) Good. Let's move on.
Dramatic Irony is the disparity of expression and awareness. So when you're watching a play, movie, what-have-you and a character is saying, doing or thinking something that is different from what you as the audience knows to be true, you're seeing dramatic irony. The situations can be comic (The jail scene in "My Cousin Vinny" where Vinny meets his nephew's friend and expects a little gratitude for taking their case while the friend thinks Vinny is another inmate . . .) , or tragic and sad ("Romeo and Juliet", anyone?).
Situational Irony is the disparity of intention and result. The irony is found between what is expected and what actually happens. This type of irony is probably what messed Miss Morrisette up. The black fly in her chardonnay, for example, would only be considered ironic if she had specifically gone out of her way to change circumstances to avoid flies altogether. Then, bam - she ends up with the nasty thing in her drink anyway. Simply finding a fly in her wine out of the blue doesn't quite complete the formula because there is no implied intent to not find a fly in her drink - other than, well, who wants to suck down an insect with their beverage? Sick. It's a fine line to draw. For what it's worth, by some definitions situational irony is not actually irony at all. . .
So there you have it, kids. Arise, go forth, and conquer. Find the irony in your life and name it so.