IT don't help themselves
As a developer who works closely with the "Service Delivery" function, the service guys often don't help themselves. I notice there was no option for "we fucked up and the phones started flashing".
A couple of weeks ago, a system "just stopped working" (it was a Monday morning - warning bells start ringing in my head). The Service Delivery boys called me up to see if I could help. It was immediately obvious the software couldn't access the database so I asked SD whether anything had changed over the weekend. They denied having changed anything.
To cut a (very) long story short, over the next two hours, in dribs and drabs, they confessed to;
1) Upgrading the version of SQL Server over the weekend
2) Moving SQL Server to a new physical Server
3) Renaming the SQL Server instance
4) Changing the name of the admin account
5) Changing the password for the admin account
Once we had the truth, it was a 30 second fix. But Network administrators (or whatever they're called where you work) acting as if they own (rather than maintain) all the hardware and making changes without following proper processes and procedures account for a fair proportion of phone calls in my experience - and I've worked on both sides of the divide and caused a fair few outages myself!