The bus I took today was very crowded. Since busses in San Francisco shake a lot, I need to hold something to stand, but the place I stand has nothing to hold. So I tried to not fall down and imagined as if I was doing surfing. Soon after the bus started to drive, a men next to me noticed that I was having hard time to stand, and he slided the rope and place it in front of me. It was very helpful. Thank you very much!!