I was very impressed by the diversity of the city, both culturally and ethnologically. When traveling by metro, the most diverse people meet and have to do all the same ... wait 3 minutes for the next subway. I had the idea to ask people for a portrait during this time.
You can meet people in this time that you would probably not otherwise meet. The interactions that took place while taking pictures were very exciting. I have learned a French sentence - "Peux-je faire un photo de toi?" (May I take a picture of you). Certain people simply had that special charisma that inspired me to ask them for a photo. For exactly these people, the answer to my question was always "oui".