As a travel agent, one of the best things is that we get to travel a lot.  Sometimes our friends or family can't go with us so, as a travel agent I get lots of single travelers who want to share costs, so, I've shared a number of times through the years with clients from different places. It's better than sharing with a complete stranger, but, oftentimes it's really the same. 
I once shared an all gay Caribbean cruise with an older gentleman client of mine. I'd never met him in person, but, he seemed like a nice enough guy and it would save me money (no, we don't always get to go for free).  So, I meet the guy in person on the ship and he's really old (late 70's) and in pretty bad health.  He couldn't get around too much (he was a BIG man), and, had a colostomy bag, and was kind of a mess.  Still, he was a perfect gentleman and very nice.  We had dinner a few times, and, basically did our own things, he preferring the lounge acts, while, I was more of a get out and dance party guy.  
Anyway, it was fine and, though it would have been nice to have a cute, fun, exciting guy to share a room with, the guy I shared with provided the thing that was promised with a share: I saved 1/2 price.  
A few months later I got a call from a guy who was a friend of the old man I shared the cabin with.  He called to let me know that my client had passed away.  He wanted me to know that he talked about that cruise all the time and that it was one of the best times of his life.  So, sharing with a stranger may mean little more than saving money for you, but, sometimes it's a final wonderful moment for someone else.