When you've tried to work out the major bottlenecks in your operation, and you have some success, but new, smaller bottlenecks show up that you still have to work to iron out.
"Ok so even though we moved Jim out of being the main bottleneck in Operations, and replaced him with multiple teams and team leads, we've noticed things starting to get a bit bottlenecky again, because the team leads have themselves become bottlenecks on some of the more complex operations."
by Sir Wordly, Gov. of Verbosity March 19, 2022