Okay?

How often do you hear this?
How often do you do this, yourself?

Most often speaking to a child in your care:

"You have to eat your lunch, okay?"
or
"Stop poking the dog in the nose, okay?"
or
"You have to pick your toys up then put them away, okay?"
or
"It's bed time, okay?"

I see that at least at Huff Post, someone else gets this!
https://www.huffpost.com/entry/is-it-ok-to-use-ok-the-di_b_9736782

Are you following? Are you tracking? Are you getting the gist?

Ending any request of another person whether child or adult or any age, with "okay?" is asking the other person for permission to instruct them in what to do.

The one in charge has just undermined their own authority.

Is it any wonder that many children have grown into adulthood with a lack of respect for authority?

You will never hear a court judge say:

"I sentence you to 20 years of confinement, okay?"

You will never hear a police officer say:

"I'm going to arrest you, okay?"

If an authority figure does do this, they are woefully inadequately trained.

Doing so is to remove their own authority or at least make themselves look weak in the presence of another person in their charge.

It makes sense that many children grow into adulthood in confusion. Many are unable to make complete sense of a world already floundering in the muck of gender confusion, multiples of divisions, hate, fear, frustration.

Authority, respect, courtesy are only three of the elements needed for a firm mental/emotional foundation to be able to survive as an adult out there in a big wild world.

When authority figures such as parents, law enforcement professionals, teachers, supervisors, undermine their own authority, they are setting themselves up for failure. 
One "okay" at a time.
In conjunction with that, their underlings have less respect for them, add to that the confusion of exactly who is in charge.

My, oh, my.

Seeds of chaos are being planted that will, in time, grow into multiple divisions in society.

Racial
Religious
Genders
Class
Socio Economic Status
Education
Ethnicity
Country of Origin
Physical ability

"Okay" is but one brick in the walls that spring up to cause division.

When one unhealthy habit is eliminated it's expedient to replace it with a healthy one.
A more healthy ending to a request to replace "okay" would be:

Do you understand?
or 
Can you please repeat back to me what I just said?
or
Were you listening?
or even
Understood?

When one of these replacement phrases is uttered then met with the "deer in the headlights" look, it might be useful to have the other person repeat back to you, what you just said.

With an adult, "Is this clear to you?" might suffice.

They might reply with "Yes" or even "Crystal".

Communicating clearly is so under rated. Clear communication is vital to a society to become or remain healthy as well as well functioning.
To sponsor confusion with manipulation, lack of clear communication, attempts to control others in place of having a conversation?
Yeah, buddy. 
It's the guillotining of a well functioning world. 

Here's a cool little experiment.

The next time you are in a position of authority, especially with a child, catch yourself before you say, "okay."
Replace "okay" with one of the above phrases.

Just roll it around in your mind, you'll be okay.