"It is what it is."
This is usually at the end of a conversation, where one either feels powerless to control whatever is happening to them. Mostly, what they want to control is something outside their control. For example:
"I've sent out five query letters to agents and all of them rejected me. I'll never be published. I guess it is what it is."
Instead of looking for what you can't control, look at what you can.
"Okay, my five query letters didn't work. What would happen if I sent out fifty? Or what if I sent five every single day? What if I wrote a blog, committed to writing something every single day, in order to drive readers to my site?"
Now that is something you can control.
What do you feel is holding you back?
How can you change it?