From my point of view, challenge is everything beyond our abilities or that we want to do but never tried before. For example, it was a challenge for me to talk to strangers several years ago because I was very shy and hadn't even asked a stranger for directions. But after I did it for the first time, it was not a challenge for me anymore because I had overcome the fear and considered it as a normal thing. When I entered my university, it was a challenge for me to speak and show myself to the public. And I remember I was shaking my legs behind the platform while reciting a message in front of my classmates and my teacher for the first time. Fortunately, I often took those challenges actively to overcome them, so I could speak and show myself to the public soon.

What matters most, I think, is that he/she can understand and respect me. We can share our secrets, interests, spirits and moments with each other without worry. And we can also joke with each other but never be offensive. The moments when we are together are relaxing and enjoying.

I don't know the changes in payment in other countries cuz I didn't notice them before. So I'm gonna describe those impressed me most in China. I gotta say that it was not so convenient 10 years ago when I was just a pupil and people just paid in cash. Then the Alipay was popularized in many areas. About 8 years ago, we got the WeChat Pay which is my favorite payment now. At some point, I found that we rarely paid in cash. We just put our money on WeChat or Alipay. After all, whenever we need to pay, we can just pull out our phones and scan the QR code.