The key is both. Your family member at a gas station doing something.

A photo should tell a story. In twenty years you want the memory of the story not some posed artificial set up.

Like with all stories, the setting is important so you should not discount the gas station.

I agree with you, but I would add stuff serving as a reminder. It may be also something you or people you know made. As for reminders think about a story from your life you like to tell people. I have a few photos like that, for example a parrot I have found one day. Landscapes can also work for this. I have a photo in Belvedere in Potsdam, it was a beautiful sunny day and the photo was nice even if made with 1st gen Moto G, I'm always reminded of that day just looking at that photo. Or a photo of a view from window in Supetar, Croatia.

I also prefer pictures of people, but I would generalize it to pictures that help form a memory, most are connected to people.

I think the key is "be intentional". So if you take photos of old gas stations or buildings or whatever, the reason is because... say.. you are working on a documentary project. Or a photo book/essay.

BTW, I still also shoot with 120 film and had certain themes to work on (like "color", "flower", "morning activities", etc). If I want to take (lots of) random images, my phone or DSLR is always ready.

I understand your point, though. Probably lots of us urban photographers have more gas stations photos on their drives compared to their relatives :D