Flip or flop

When I took the Metra to the city today, I discovered that my sister, brother, and their friends were on the same train. Soon after we boarded, I looked down and realized, to my dismay, that I forgot to switch from the ADIDAS sandals that I wear around the house to my black flip-flops. Luckily, my sister had an extra pair of sandals in her backpack. She loaned them to me, but only under one condition: that I blip these so everyone will know how much of a wonderful, generous, and saintly sister she is.