From Discworld MUD Wiki
Performing mend on a piece of clothing that matches the current fashion gives an additional bonus because the item is holy:
> locate worn red clothes he pair of red and white striped dungarees (worn) is in your inventory. The red badge (worn) is in your inventory. The blood red silk stole (worn) is in your inventory. > perform mend on dungarees It seems a lot easier to perform mend because red clothing is holy, you are near a stylish place and you feel comfortable in your stylish clothes.
Performing mend on a piece of clothing that opposes the current fashion gives a penalty because the item is an abomination unto Gapp:
> perform mend on green trousers. You find it much more difficult to perform mend because you are far from a stylish place and green clothing is an abomination unto Gapp. However, this is partially mitigated by the fact that you feel comfortable in your stylish clothes. You consider the art of weaving. You hold aloft a pair of green trousers, and feel Gapp's presence around you.