When something goes wrong, people commonly say: "It is what it is."
So, if Afghani soldiers don't show up on time to start an attack, Aussie soldiers might comment: "It is what it is."
If employees find out that their new supervisor is widely known as the boss from hell, they might say: "It is..."
"It is what it is" has never meant much to me, other than providing an air of resignation about some development. I reckon we could replace it with something shorter like the title from a Frank McCourt memoir: 'Tis.
If we want more info about some event, we can ask the person speaking to explain. That request is likely to be met with a blank look, followed by a rephrasing: "The situation is what it is." No wiser for our effort, we might then give up.
If you want to use the expression, here are some rules to follow.
The main rule is that the development must be a bad one. We never use the expression when something good happens. I have never heard a person say about receiving a big promotion at work: It is what it is.
Here is another rule of saying "It is what it is": The bad development cannot be VERY bad. I do not expect a person to remark about the death of his sainted mother: "It is what it is."
Another common expression that competes with "It is what it is" for being low in content is: "Such is life." If you want to add pizzazz to your speaking, use the French equivalent: C'est la vie. If you want to go crude, say: "S%&# happens."
These words fill a void when we do not know what to say about a bad development.
If we are tempted to use the expressions, we can be more forthcoming by saying something like this: "X is a bad development. I feel concerned, but I don't know what to do."
Or, if you are a fan of the Seinfeld TV show, use this line of Kramer's: "You're FREAKING me out!" Like Kramer, put some emotion in your words.
That kind of emotionally honest statement might trigger a useful discussion that leads to a solution or at least to receiving social support.
But we don't always want to discuss a problem, so keep ready some version of "It is what it is."