McCartney is proudly anti-harm when it comes to using animal-derived textiles in her clothes. For her fall 2015 collection, she sent head-to-toe synthetic fur down the runway with "fur-free fur" stitched somewhere visible. (This could be particularly helpful if you happen to be famous — like, say, Anna Wintour or Samantha Jones — and in the presence of protestors as you enter and exit shows.)But back to the dancing.Every season, the relevance and evolution of Fashion Month is discussed and debated at length, but this time around, we're just glad that McCartney gave the models a chance to let loose. The designer's spring 2017 show combined über-functional clothing with a simple — yet, sometimes, necessary — ingredient: some good ol' fun.