I have a horror story that will send chills down any admin's spine.  A few years ago we had a major deployment over a long weekend and nothing worked.  We were hitting validation rules each time we tried to modify or create records and couldn't figure out why.  Decided to pull up the audit trail and was shocked to find out someone had deleted ALL the Profiles.  When questioning the "Admin" he did admit deleting the Profiles and his reasoning was it was much easier to Recreate the Profiles then to modify them one at a time with the new field security but he did have a rollback plan which was to use an app to recover the IDs.  Long story short we put in A LOT of OT to realign the new Profiles and this is the beginning of the Tales of the Rogue Admin.