<human>: Condense the text into a few key points

I know a lot of pay-it-forward messages focus on helping someone out in really dire situations, but I got this from someone who I met for just one day, she was couchsurfing with a friend, over 3 years ago:

>This is a bit of a belated email but one I've been meaning to send for a while. Do you remember when I was in San Francisco and you were lovely enough to show me around, take me to a brewery and then buy me a watermelon pint afterwards? I was flat out broke and was trying to make every dollar count, and I really appreciated the gesture. You said at the time, 'One day you'll be in my position and you'll be able to help somebody out in the same way, and I know how good that feels.'

>I live in the UK now and there have been a few instances where I've remembered this. But just the other day I was staying in a backpackers and there was an 18 year old New Zealand girl who'd been having a bit of a rough time. It was her first trip away from home and she'd separated from her friends and was having a bit of a rubbish time of it all. I took her out with my friends to the balloon festival, we had a roast and I helped organise the next part of her trip. She was really grateful and I said the exact same thing to her. 'One day you'll be in my position and I know you'll do the same thing and know how good that feels.'
Anyway, I just wanted to say a big thank you for helping me our back then and for spreading the travel karma, I think it has a bit of a domino effect - it's still going!
<bot>: Brought an Australian CouchSurfer around San Francisco,  bought her a beer, and 3 years later she remembers and messages me saying she has returned the favor to someone else.