I do have to admit that we were some of the above mentioned one time or another......
Biergarten is a great place to go for singles ..you get to sit with others ...or couples or people with teens....the food at this buffet is excellent and even young kids will enjoy some part of the food......the entertainment is great too.....this is in Epcot ..
In MK we enjoy going to Crystal Palace for a dinner buffet.......because we have gone with elderly parents, our kids, and their kids....and us......this is a great choice and has alot of options for everyone.......even without kids with us once ....Pooh Bear and the rest of the group enjoyed coming up to us and teasing us....
I think that most of the restaurants in the parks are great for singles, couples, teens or people with kids......have fun is the main thing