Re: SLAs make work for idle hands...
"Here's me thinking : yeah, well maybe you should have enquired about what you were leaving and what the replacement tool could do to fulfill the need."
Absolutely. Mid 80s, I was working for a small company, dealership for a particular niche-but-well-regarded accounts software. I'd not long helped install some nifty full tower 80386 machines at a client, a pair of which supported some 30+ serial terminals, when the client decided they'd had enough of us, and switched to the other local dealer. Fast forward a few years, I got a job at this other dealer too, and found myself installing a whole new system at this same client.
It seemed that in the intervening years, they'd got fed up of the new dealer, my new employer, and tendered out for a whole new system. I don't know who or what they chose, but it must have cost them a packet, as it involved PCs on each desk instead of dumb terminals, and thin ethernet everywhere. Then they tried to actually use it.. Apparently they had gone to the new company with a list of everything the existing software couldn't do, and were promised that the new software either could, or could be made to do all those things.
Of course, and I know you all spotted this coming, they forgot about listing all the things that the existing system /could/ do. So they start trying to use the new stuff, and it can't do most of what they were used to doing..
So they came back, cap in hand, to my new employer, apologising profusely, and we set everything back up as it had been, and were also able to address their list of Things It Doesn't Do. They didn't try to jump ship again, at least not in the time I was there. I don't know now - my now long since ex employer has switched over to selling SAP...