There are two ways to make improvements in the world: you either reduce or eliminate that which is bad or you create or increase that which is good. For example, the list of bad things to eliminate could include curing various kinds of cancer, or reducing or eliminating hunger, or wiping out malaria, or reducing the number of animals that are euthanized or in shelters, or reducing environmental pollution, or are reducing the incidence of wrong beliefs in the world.
In an Ideal World
Everyone has a life partner. No one is lonely. The process of finding a compatible life partner has been vastly improved.
Everyone who is working is working at an interesting, meaningful, fulfilling job. No one hates their job. There is no unemployment.
Everyone develops their full potential.
Everyone has a sense that they are making a significant contribution to the world.
No depression.
Rich communication across scientific disciplines, accelerating the pace of discovery.
No physical, emotional, and verbal abuse of children, women, or men.
Well-educated electorates.
Equitable distribution of wealth and income
Everyone is physically fit. No one is obese or malnourished.
We have stopped pumping huge amounts of carbon into the atmosphere and global warming has stabilized.
Everyone has a clean, comfortable home.
Everyone is eating nutritious meals. There is no food insecurity or starvation.
[Reverse These]
Mental illness
Environmental degradation and pollution
Discrimination (on the basis of race, sex, sexual orientation, etc.)
Excessive personal debt
Excessive collective (national) debt
Lack of critical thinking. Irrationality. Forming beliefs without evidence.
Unchecked political power. Lack of democracy.
Aging and physical deterioration.
Sexual repression, dysfunction, and pathology
Human trafficking for sex or forced labor
Drug and alcohol abuse
Industrial agriculture
Cruelty and neglect of animals
Animal euthanasia
Unwanted pregnancies
Sexually transmitted diseases
Suicide
Bullying
Illegal immigration
Politicsl corruption
Lack of education. Ignorance of science, history, and other branches of knowledge that seek to understand the world.
Lack of access to affordable healthcare.
Incurable diseases (e.g. various forms of cancer)
Cardiovascular disease
Lack of access to efficient, affordable public transportation
Ugliness
Traffic