Accidents are unfortunate events that happened unintentionally, while risky behaviors usually intentional even though the negative effects are already known.
One example of accidents is if plane passengers died during the plane crash. And the example of a risky behavior is to use tobacco product despite the negative effects it has on health.
An alternative rock singer
Yes, I agree. Since it's a relatively new technology, there's little research to establish the long-term consequences, good or bad, of social media use. However, multiple studies have found a strong link between heavy social media and an increased risk for depression, anxiety, loneliness, self-harm, and even suicidal thoughts.
Yes a premature death can occur if the dimensions of health are underdeveloped.