Another fun one... Should I be Worried About Scaling?
What happens when the comfortable SQL world of yesterday changes out from under you? You feel like this (it uses some language picante so be advised):
Here's a link to the source: http://browsertoolkit.com/fault-tolerance.png
A great way to communicate the dislocation one feels when technology changes. It also gets you to wonder if those changes at the user level are completely necessary for carrying out the task?
Lest you think this just an old guard reactionary sentiment, Boxed Ice chose MongoDB over CouchDB partly because "CouchDB requires map/reduce style queries which is much more complicated to work with."