Meaning of おしまい in Japanese

What do you say to calling it a day?

That's enough for today.

It's all over for us.

Once you hesitate, you are lost.

If the tip was a dime in one glass, the waitress, in her haste to get the table ready for the next customer, would pick up the glass, the water would spill out, and that would be the end of it.

It's all up with the firm.

Let's break up the party.

This is it. They're going to kill me.

Let's quit and go home.

Once you are married, you are done for.