salary is paid, retrospectively

What does it mean to be 'employed'? OR What does it mean to be as an 'employee' in terms of money?

When we employ someone, we agree that that person will work in an assigned capacity and be paid an agreed sum after a month. When we are an employee, we do what is assigned and when the last day of the month arrives, we expect to be paid the agreed sum, or what we call 'salary'.

What happens when after a month, the employer says, he needs to review the work you have done, before he signs off on your cheque?
I say, TROUBLE.

This is what a friend of mine couldn't understand.
I was explaining that when companies hire, they have to pay what's contracted, without questions. If the employee is not suitable for the job, then the salary STILL NEEDS TO BE ISSUED, and a notice given for termination.
Frankly, I have never, ever come across a similar situation like this, where a contracted staff is being refused payment, until they reviewed his work. Work appraisals come once a year or whenever the company is doing a down-size, upsize, or shuffle.....not when salary is due - that to me, is too convenient a way out.

Strange thing though, my friend, didn't think there was anything wrong with that. I suppose when you're working for your cousin, you need to probably make sure you're on your cousin's side, but what happened to employees rights?
It's sad when people decide to pay salary retrospectively.
Thankfully, this is the first I've come across.