I'm guessing by the timing this is relating to the Melbourne Cup, a public holiday centered around a horse race, and the fashion has become synonymous with the races. The women dress up with expensive outfits, and it's quite a thing for girlfriends to have a "Cup Day Lunch" out somewhere. Prettymess is pointing out that we don't need to have a reason such as the races to get fancy, especially considering the treatment of the animals in preparation for, during and after the race. Quite a related note, actually