Apathy.
Most if not all the major issues that plague society, such as global warming, deforestation of rain forests, corrupted health care, poverty, imperial wars, and corrupt economic systems are solvable with today's technology, knowledge, and industry. The problem is that many of the people who are able to solve these issues or contribute to solving them don't care.
An issue can have a million solutions but if no one cares about it then that issue will never be solved and that is the current state of most problems.
If people could lose their apathy towards everything that isn't themselves or doesn't directly affect them in the short-term then I think we could actually do something good for society and thus each of us.