I still remember a server one of my classmates hosted was basically unplayable for a few days. I was admin so I saw console messages talking about “oversized chunks”, so I went to look for the oversized chunks, and I found two things: the CHUNK was 12MB, and at the location of the oversized chunk, I found a string dupe machine that one of my stupid friends forgot to turn off. Was fun seeing their reactions after finding out that they caused the issues themselves 
(Also we were using hosting service and the guy who bought the server is very rich so we got very good specs, I think we have 20GB memory or something)