Norwich - a fine city

I know I've jested about the city sign on the A11 saying 'Norwich - a fine city', but I recently had an experience to prove that it is. And it's a fine city because of the people that live in it.
I was walking from one office to another with an envalope in my back pocket containing some cheques and a paying in slip that I intended to put into the post to my bank so as to pay the cheques into my account.
When I got to the post box the envalope had gone. I'd clearly dropped it at some point. I retraced my steps, asked the security guard at work if anyone had handed it in and then got the creators of the cheques to cancel them.
Mean while, some good samaritan had picked up the envalope had seen that it was destined to for post and put it in the post box on my behalf.
To whoever that nameless person is. Thank you.