- Prior depictions of the desert show it to be a Year Outside, Hour Inside type of place. How then could Barbara return in time with the sand worm if even seconds there translate to hours in the real world?
- Death causes paperwork for the Celestial Bureaucracy that is the Afterlife. Suicide causes more death which causes more paperwork. Therefore, suicide victims, who had killed themselves with the hope of either ending their pain, or possibly getting to heaven, are punished for causing more paperwork by having to file that paperwork during their time as ghosts. It doubles up to teach them that suicide doesn't end your problems, while at the same time not condemning them to Hell.
- Every dead person seen in the movie(even the Maitlands are dripping wet and pale, and sharp eyes will notice Barbara's neck is broken) has an instantly-recognizable cause of death; a woman sliced in half by a magician's trick gone wrong, an obese man choking on a chicken bone, a smoker who burned to death who's still insists he's "trying to quit"(who likely died because he went to sleep with a lit cigarette), and of course the obvious suicides - slashed wrists, hanging from a noose, flattened by the car they jumped in front of. The suicides are all bureaucrats stuck processing the paperwork, and the Maitlands are actually processed faster than the people who got themselves killed by easily-avoidable causes - and after they're processed, they are given lots of help. The Afterlife plays it tough but fair; if you were just minding your own business when you died, they'll do the best they can for you no matter how stupid you are(QED the dumb football team), but if you were pushing your luck, they consider it almost as bad as suicide: hurry up and wait, jerk.
- Lydia, being a goth teenager, is perfectly willing to make a stupid decision which will have eternal ramifications (by killing herself) in order to stay with the Maitlands. They save her from this, but later, during Otho's exorcism, the only way she can save them is by saying those three little words and getting married, exactly the same sort of stupid decision many other teenagers have made, regardless of the consequences. Worth noting that the Maitlands are exorcised wearing their wedding clothes, and Beetlejuice is defeated a split-second before the minister finishes saying "I now pronounce you man and wife."
- Even if Betelgeuse got married, the sand worm eating him would have still worked, since he'd be mortal again and still died.