What was a video store? Like a library for movies?

I always thought it was like that, but surely they had libraries with movies to rent too, right? So, was it instead a kind of hang-out space to buy movies, like a record shop?

What was the deal with the shady stuff behind the counter or something, or like in another room? Was that where the ‘adult films’ were? I’m also curious how they enforced things like age ratings and quality of returned movies if rented—did they train the staff a lot for that like in cinemas?

And did they have other things, kind of like a gas station or corner shop? Like snacks, music, etc? Maybe these are all obvious questions but I was curious what those who really went there would describe it as. Also, would you swap back if given the chance (were there even that many)?