The universe is, as I'm sure we all know, around 93 billion light-years across in size, when measured from here to here. Just for a bit of context, a light-year measures around 10 trillion kilometers, or roughly the same distance between where BMW drivers park their car, and the actual space they were aiming for.
Yet despite the sheer improbable size of the universe, Star Trek absolutely loves to have familiar faces come across each other in it. Of all the gin joints, on all the space stations, in all the cosmos, she walks into this once that just happens to be run by everyone's second favourite Ferengi. The first is Rom.
And as well as sharing the actual universe, the franchise is in itself a shared universe, meaning that writers are always free to pluck a character from another show and drop in elsewhere if it fits a strong narrative. Or, in the case of Lwaxana Troi, even if it doesn't.
From flying visits to entire bottle episodes, let's look at all the times Star Trek replicated itself a little charachter buffet.