"Kiss Me I'm Irish" has nothing to do with being Irish, but it has everything to do with the pop culture quote, which is, in a way, what defines this universe. It is never supposed to make that much sense or strictly follow the path of logic. Sometimes it's nonsensical or just plain silly. It is there to entertain, not to hold a bar for valuable works of fiction.
This is meant to stray from the overly elaborate and "explained" media out there.
The setting is divided in two planes, which sometimes intersect.
One plane is planet Earth, which is pretty much our current day Earth. People are unaware of the existence of aliens or have not yet found proof of life on other planets. This doesn't mean they stopped trying.
This plane generally comes into focus when Miranda comes home for the holidays or on other various occasions and it focuses on her relationship with her family, going on dates, regular day to day things. As I have mentioned, her family has no idea what she actually does.