What do you mean by “Event-Driven”?
One common anti-pattern is that "event driven" can lead to a push architecture that works on paper, but is unreliable in practice.<p>The idea looks deceptively simple.  If you need something to happen, you just broadcast the right event, someone else acts on it and everything is fine.  You code it, it works in the demo, and you deploy to production.<p>And then you run across network failures.  Missed events.  Doubled events.  Events that arrived while a database was down.  Events that were missed due to a minor software bug.  And so on.  You layer on fixes, and the system develops more complex edge cases, and more subtle bugs.<p>Then you rewrite from a push based system to a pull based system, and all of your complex edge cases disappear. :-)