The 30-something works 12 hours-plus, seven days a week, earning up to 5,000 yuan ($756) a month. It's a sum Xu dared not contemplate when he idled away his days at Sanhe, his first stop when arrived in Shenzhen from his native Henan province seven years ago.

Snaking through the dense, tangled warrens of the urban villages nearby, he was shocked by the incredibly low living costs in the area, which is dominated by small and medium-sized businesses.

Urban villages have long served as enclaves of cheap housing for the migrant workers who have supported Shenzhen's economic rise.

"Thanks to the lively urban villages, I've had no difficulty finding internet bars that charge 1.50 yuan per hour and 6 yuan for a night." Xu said.

"Shabby hotels offer a bed for just 15 yuan and a single room for 30 yuan a night. At the Shuangfeng Noodle Restaurant, a bowl of noodles sets you back just 4 yuan, and it has never raised its prices. This is a wonderland for low-paid workers. It's equally a playground for job-shy people who just muddle along and idle their time away."

Second generation

Xu's parents were among the first generation of rural workers who left their farms to work on assembly lines or construction sites in coastal cities. That generation is about to retire.

When Xu replaced his parents as part of the second generation of migrant workers, he refused to repeat their dull lives.

"Working in factories means you are more or less chained to production lines. You punch in, punch out, and repeat the same cycle the next day. I just can't help asking, 'What's the point of living a life like that?'" he said.

He ended up signing up at Longhua's "Sanhe dashen club" as an "on call" worker, but he threw away five years, lost and paralyzed by guilt.

"By the time I realized I could not do that anymore, it was already the winter of 2015. I fled Sanhe and found a full-time job in Shangtang, putting an end to that unbearable existence," he said.

Fang, the Longhua resident, noted how the unemployed stand out in the city. "In Shenzhen's congested and hyperactive urban environment, it can be mind-boggling to see the likes of Sanhe dashen living in such a hyperpassive way," he said.