I often see people crying on the tube. Usually they are a seat away or across the aisle, they feel just a bit too far away to do or say anything in an unobtrusive way. Today I got on the tube, it was quite busy but I realized the girl in front of me was crying. I offered her a pack of kleenex and asked if she was ok. Of course she said she was ok. By the next stop she was able to find a seat. When I got off the tube she waved to me and mouthed thanks, while still crying.
Sometimes places that are so full of people make you feel very alone.