"You need this when?!?!"

"Our competitors somehow seem to know these things before we do -- isn't there a way you can get this to us sooner?"  "We just found out about this and need information immediately so we can determine how to deal with this situation."  "The computer does all the work, so it won't take long to do this, right?"  "I know you are working on a hundred other things, but this is really important and won't take too long ... "

In the best of all worlds, we could plan for all eventualities, anticipate all developments, deliver everything yesterday and still have enough time for life outside of work.  As we all know, in the real world, some things cannot be foreseen, some priorities will conflict and resources always seem to stretch too thin for addressing everyone's needs. Headcount constraints, special projects or other peak demands on resources require support from someone who can hit the ground running.