It depends on if they know each other or not. I generally ride with people that I know. I suppose if you don’t know the person you got stuck with that you would introduce yourself. The conversation would probably veer towards how awkward the situation is, the weather and also how quickly they are going to get you down. I mean I would be freaking out because I would be terrified, I would have a friend who would calm me down though so I would be ok. If I was just stuck on a roller coaster with someone I didn’t know I would probably keep my freaking out to the inside and try and remain calm on the outside. I don’t know how well this would work. I would also be really open about anything and everything with the complete stranger. I am in general a very open person. Hopefully we wouldn’t be stuck up there for very long. I am imaging that we are not in the middle of a loop, where we would be upside down. If we were I would freak out openly and we would probably pass out at some point.
Image from google image. Sorry for this weird rambly post. Time Magazine is where the image came from.