What often happens one week before a conference deadline...
Proof-reading a preliminary manuscript.
Adding in some details.
Finding small, or, perhaps, not so small errors.
Spending more and more time on it.
Delving deeper and deeper into a proof.
Suddenly having some ideas for a new result.
Shifting into "DEAR" mode, as they say around here in elementary school: Drop Everything And Research...
.. And that is why being organized and on-time is an elusive, never quite reachable goal in research jobs.