I didn't understand that

 Until I saw this commercial where the person says she was business casual 

Today

 Its the wearing pajamas outside 

Back in the day

 Casual dress was jeans 

And if we did

 It was on a Friday and we had to pay 2$

Or just as a general rule

 We couldn't wear blue jeans to work 

I don't know where I was

 Working 

That was good

 Until the person you thought you were talking to was really not that person 

Then it was

We meet online on the computer 

I don't know like

 While Craigslist was a thing I have never been on Craigslist 

And then came

 The Craigslist killer 

Like Craig's

 List