The person I'm thinking of is my flatmate Lin, who I met when I moved to Guangzhou for work about three years ago. She works as a physiotherapist, and I'm an accountant.
Before I met her, I firmly believed that exercise was a waste of time for someone as busy as me. I used to say that I sat at a desk for a living, so I didn't need to be fit, and that gyms were for people with spare hours. Every time someone suggested going for a run, I had an excuse ready.
Lin didn't argue with me, which is probably why it worked. Instead she just explained, quite casually over dinner one evening, what she sees in her clinic every day: people in their thirties with back pain and stiff necks from sitting for ten hours straight. Then she asked if I'd try a ten-minute stretching routine with her before work, just for two weeks. I agreed mainly so she'd stop asking. Within a fortnight, the headaches I'd had for months had mostly gone, and I was sleeping better. After that I started walking to the metro instead of taking a taxi, and now I go swimming twice a week.
How do I feel about changing my mind? Honestly, a little embarrassed at first, because I'd been so stubborn about it. But mostly I'm grateful. I've realised that the opinions we defend most strongly are often the ones we've never actually tested. Lin didn't make me feel stupid; she just gave me a small, easy way to find out for myself. I try to remember that whenever I want to persuade someone of something.