They hate it when you come in just before the store closes, and keep them there late, then leave without buying.  They hate that!

Every car dealership on the planet will stay open until the last customer is gone. So if it happens to be one of those 12 hour days and a customer comes on the lot 5 minutes before closing the sales person is expected to spend as much time with the customer as it takes to put a car deal together.  This could be 2 or 3 hours or more!  When I was selling there were many times when I couldn't leave the dealership until 11:00 or 12:00 at night.

When I was selling, I had a rule.  If I took an "up" (that's a customer who walks on the lot) with a half hour or less to go before closing, especially on late nights, that person was buying something before they went home.  I didn't care what it took!  I'd lock the dealership doors, hide their car keys...whatever it took to put them in a car.  At that point it became a battle of wills!

When a salesperson has a customer past closing, the sales manager and the finance manager have to stay late too!  It makes for a very cheerful bunch of people!

On the positive side it is a great time to make a car deal, because the sales crew want to go home.  They're likely to take any kind of deal that is remotely within reason.  This is good for you!