- Lack of decent public education

- Lack of decent healthcare

- Lack of basic infrastructure, in a lot of favelas, they don't even legally have electricity

- Jobs are scarce, favela's citizens usually endure long commutes under the very inefficient public transport system to work low-paying jobs

- Rio's favelas are usually located in hills, when it rains, landslides are very common, more often than not they are deadly

- Most favelas are dominated by heavily armed drug dealers (most of their weaponry are semi-auto rifles coming from the USA), law-abiding citizens often see themselves under gunfire between rival gangs or cops

- Citizens are often extorted by drug dealers, or even corrupt cops. They need to pay a "protection tax" in exchange for basic services

I could go on and on ...

Source: Born and raised in Rio