Let's look at this via a metaphorical cliche.

At a former job I was dealing with several different assignments at a time. When new ones came in, I asked for priorities so that the most important tasks got done first; to which my boss (female, by the way; I have no idea whether this is relevant, but see Laura M. and Clementina's comments) replied that they all were important, they all were needed right away, and I should learn to "juggle" them.

Which sounded good and business-y, of course -- until you examined that figure. Catching a ball and returning it to the air takes the same amount of time no matter how many balls are involved. What changes with additional balls, therefore, is the time between when each ball leaves your hand and when it returns. The more you have, the less attention each one gets in a given period, and the longer the overall process takes.

Leaving aside the obvious joke about what it takes to do this kind of juggling, I'll say only that this metaphor is most commonly used by people who haven't followed it through to its implications.