Before World War I and World War II, many thought things would not escalate until we realised it was far too late. The British intelligence thought the assassination of Franz Ferdinand would only be contained regionally instead of escalating to a world war.
Most wars are class wars and most issues are class issues. But most people are not class conscious. The base tribalism is instead drummed up to distract us from the real root cause. We're seeing the rise of the far right in many countries such as in Europe, US and India. Most of the rise of the right is due to influx of migrants, who are displaced by neocolonial foreign policies of corporate backed governments and capitalism-induced global warming.