Explanation for no 2-door cars: It was unchristian to drive something that would inconvenience other publishers in service by having them climb out of the back seat.
Some I recall:
Can't pierce your ears because God didn't put holes in them in the first place.
Couldn't chew gum at the hall.
Couldn't wear sunglasses in field service because the householder wouldn't be able to see if your pupils were dilated and you might be stoned.
We had to call Lucky Charms...Fortunate Trinkets.