Traditionally, like many things in life, the economy works in cycles and has fairly consistently followed certain patterns throughout history. The advent of the internet and globalization may have slightly shifted how that works now, maybe resulting in shorter slumps that recover quicker but everyone can make the wrong assessments when times are good. The financial crisis took many years to build up, hidden in the background, before it created the biggest shocks to banks in history. The thing about recessions is the causes are never the same as the last ones, so they are hard to pick out and decipher where the next shock will come from. Maybe it will be triggered by an escalating war, maybe there will be an earthquake somewhere important to global supply chains - no one knows.