The first thing I thought of was the story Flatland.. but that's more about dimensional differences. It probably applies though. It's about 2D/two dimensional beings who have no concept of "up or down". What if someone from our dimension interacted with them? It wouldn't go very far. They'd hear voices coming from nowhere, for one. If they don't run away or think they're insane, then you might be only able to interact with them through clever shadowing and reflections or something. And as for "Planes" specifically, I'm assuming "another reality" would be just as dramatic. They could living with entirely different rules and paradigms. Nothing would make much sense. If you mean someone who lives in a magical fairy or alien world, but pretty much can do similar things, like walk on two legs, interact physically, speak, etc.. then I don't see a big deal.
I was imagining a teleconference wedding taking place on two private jets where the bride's side is on one plane, and the groom's side on the other.
Accept the past. Live for the present. Look forward to the future. Robot Fusion
"As our island of knowledge grows, so does the shore of our ignorance." John Wheeler
"[A] scientist looking at nonscientific problems is just as dumb as the next guy." Richard Feynman
"[P]etabytes of  data is not the same thing as understanding emergent mechanisms and structures." Jim Crutchfield