The challenge of event thinking is that the IT designer must accept uncertainty. In transactional systems the callers request is guaranteed to be fulfilled or the caller will be told of a failure. In event-driven systems the source cannot be certain that their intent (if any) will be fulfilled: the event handler has full control of the reaction to the notification and may or may not do what the source expects. This uncertainty is 1. Completely contrary to 50 years of IT focused on guaranteed integrity of action and 2. is a better model of real life where all agreements have some degree of the leap of faith. The first, at the core, is why it is so hard for event thinking to take hold. The second is why the digital business success demands it.
Read Innovation Insight for Event Thinking for more Gartner guidance on event thinking.
Read Gartner on Event Processing in Digital Business: Recent Research for more Gartner guidance on #EventDriven.