Superstore Grandpa; I hope I see you again one day!

I was standing in line to pay for groceries at superstore today, when I noticed this Chinese grandpa behind me was struggling to unload his cart of food. So I turned around and offered to help him, to my surprise he spoke perfect English, but was super defensive. “No!” he said. :[ Gosh, that made the mood awkward, so I turned back around, but then to my surprise he compliments me, asking me why I’m so nice from behind. I was taken aback, I never considered something like this as being nice. It was a really good feeling though. So I helped him unload his cart, even though he was like - no no, I then proceeded to pay my groceries, contemplating whether I should stay to help him pack his groceries too. But I didn’t want to be intrusive and annoying, and gah, so I left. I feel so guilty, I should have stayed to help him pack his groceries. 

Note to self, help all grandpas in need!