Bound feet
During a conversation in the office today I remembered getting on a bus in a city somewhere in China in the late '80s. As soon as I got on the bus, an old, crouched lady, couldn't have been taller than 1.5 meters, at least 102 years old and with skin like leather, got up to let me have her seat. When I tried to politely decline her offer and ask her to sit down again, she refused. That's when I realized she had bound feet. They can't have been bigger than the feet of a little child and she'd probably fall over if I looked at her too hard. I tried to decline her offer again and get her to return to her seat, but she persisted in her refusal. In the end, I lost the battle, and had to sit down. Having an old woman with bound feet get up to offer her seat and then just leave the seat empty would have showed an extreme lack of respect.
So that's how I stole a bus seat from a poor old woman with bound feet.