Whilst The Duchess (who hasn’t been seen for quite a while) is titular ruler of Borogravia, it is the clerics who seem to make most pronouncements; and these entirely consist of Abominations Unto Nuggan, the deity worshiped in the Duchy. Each such edict only makes life harder for the oppressed population. Discworld Stamp Collectors have had two offerings involving Abominations, the first being slips found in the Little Mother LBE.

I am not sure how many Abomination slips there were, but 20 were reported. This is the full list:
THE SMELL OF THE BEET is an ABOMINATION UNTO NUGGAN
Grow not the beet on soil that has known the vine or grain. For it is an ABOMINATION UNTO NUGGAN
That which is STONE and called ROCK is an ABOMINATION UNTO NUGGAN
Those hideous flaps which listen to SIN are an ABOMINATION UNTO NUGGAN
Neither grow nor eat the stenchful bulb GARLIC For it is an ABOMINATION UNTO NUGGAN
Messages that do fly in the firmament do fly in the face of NUGGAN and are thus an ABOMINATION UNTO NUGGAN
Make not the graven image that doth not Glorify your GOD for it is an ABOMINATION UNTO NUGGAN
That which is BLUE OF COLOUR is an ABOMINATION UNTO NUGGAN
Any SHIRT that hath BUTTONS SIX are an ABOMINATION UNTO NUGGAN
Wear not the apparel of the woman if thou be a Man for indeed it is an ABOMINATION UNTO NUGGAN
Wear not the apparel of the Man if thou be woman for indeed a Blasphemy and a ABOMINATION UNTO NUGGAN
Those of the FELINE specie are an ABOMINATION UNTO NUGGAN
The DOGS that bark and disturb the faithful are an ABOMINATION UNTO NUGGAN
The evil denizen of the deep called OYSTER is an ABOMINATION UNTO NUGGAN
The dwarfish race that worships Gold is an ABOMINATION UNTO NUGGAN
The mewling BABY is an ABOMINATION UNTO NUGGAN
The hideous noise of the ACCORDION is an ABOMINATION UNTO NUGGAN And those that make it shall be DAMNED
The long hair of the woman is a distraction to the Man and is thus an ABOMINATION UNTO NUGGAN
All that is made from the heathen Chocolate is an ABOMINATION UNTO NUGGAN
Eat not nor make the CHEESE for it is an ABOMINATION UNTO NUGGAN

A further postal link came with the Borogravian three pence stamp where the sheets alternated the stamps with labels carrying Abomination messages. Some of the above were repeated, but clearly the clerics had been busy as there are some new contemporary Abominations added. I suppose the idea was to leave the label attached to the stamp when it was put on the envelope. Not only does it act as a reminder to the addressee, but it would give the pious sender a dose of satisfaction. Of course the sender could perhaps chose one appropriate if the addressee had not been observing certain Abominations.