Earlier this year, anger over the perception that Hong Kongers were unfairly burdened with extra costs incurred by the Chinese was vented in a full page advertisement in a local newspaper which referred to mainland "locusts."
The ad followed a surge in the number of pregnant mainland women crossing the border to Hong Kong to give birth. In April, incoming chief executive CY Leung announced a ban from next year on mainland women, without a Hong Kong husband, giving birth at local private hospitals.
"It depends on how you see the Chinese people," said Ernie Chu, who runs a pet supplies shop and daily dog-minding service charging $120 (U.S. $15.40) a day, around the corner from the Sai Ying Pun market. "For business it's good because there are a lot of chances to grow the business, but on the other hand it's a burden to Hong Kong."
The government has already introduced measures intended to cool the local housing market, but they have not yet made a major impact on the poorest members of society.
Hong Kong's inflation rate rose 4.3% in May, compared to the same period last year. It was slightly less than the rise recorded the previous month which the government attributed to easing food prices and a smaller increase in private rentals.
Mary declines to be pressed on whether she's hopeful that things may improve for the residents of Hong Kong in the years ahead.
"I'm so old, so I always have to keep my spirit up and I always look at the bright side of things," she said. "I always stand facing the front so my shadow is behind me.
"There's a Chinese saying: You have to believe tomorrow is better. Always have this belief the tomorrow is better."