A subject that seems unavoidable at the moment is group thinking. By this I mean when people think of themselves as members of one group, and judge other individuals based on the group to which they belong.
We are currently experiencing violence in our region between two different groups. Both groups have a claim to the same territory, and because they are so intent on preserving their separate identities, they cannot just share it.
Ideally, we would treat all people as humans, and issues like ethnic origins, religious faith and language would be matters of personal choice (or chance) rather than labels that become more important than individual traits. I would like to live in a world where nobody asked "What are you?", meaning "What is your race/ religion/ other group label?". Nobody would be upset if their relative married a member of another group, provided the relationship between the two individuals was based on mutual understanding.
In practice, so many people are willing to kill and die for their group identity, and to subject the world to chaos, violence and suffering in the process, rather than admit that we are all human and find a way to live together.
Having said all that, I am not a naive idealist, and I know that it is unlikely that people will give up their group thinking and adopt individual thinking. I also know that there are differences between various groups in the degree to which they are willing to accommodate the needs of other groups. Some groups have an ideology of wanting every human to join their group and adopt their way of thinking. Others just want to continue their existence while cooperating as much as possible with the surrounding groups.
Tolerant individuals must be aware that not everyone is equally tolerant, unfortunately. In order for tolerance to survive, it sometimes has to take what seems like intolerant action against the intolerant people who seek to impose their ideology on everyone else. Obviously this is not easy for tolerant individuals who see the other side as individuals and are aware that not all members of a particular group are involved in the intolerance.
When hearing about a conflict, I believe it is possible to identify the motivations of each side and to evaluate how much each side contributes to tolerance or intolerance in the world (assuming that one searches for the facts rather than accepting propaganda). In this way, one can decide which of the sides seems to be, let's say, slightly less unjustified in using violence against the other.