There’s a difference between "having a lot to do" and "being busy". 

I almost always have a lot to do.  I have a long list of tasks and projects that I’m interested in doing and I can productively work on that list at the drop of a hat.  By the same token, I can usually stop what I’m doing and do something else if the need arises.  There are certainly some tasks that require uninterrupted time, but those are easily accomplished in the "off-hours" of early or late.  Most of the people that I enjoy working with structure their work similarly: they’re never "busy", but they are constantly making progress.

The people I least enjoy working with are the "busy" ones.  These are the folks who feel buried by their tasks and often when asked to do something (and almost always when asked why something didn’t get done), their response is "I’m very busy".  The worst part is that everyone seems to take being busy as a universal and unquestionable excuse instead of immediately responding, "Well how did you let yourself get into this predicament?".  My friend, and never-busy-colleague, Jimmy C once pointed out that being busy is a choice just like being drunk is a choice.  He likes to say, "Replace the word ‘busy’ with ‘drunk’ and see how much weight it carries". 

"Sorry, I can’t help you out, I’m too drunk" or "He’s a very drunk person" or "I didn’t get to it yet, I’m too drunk".

Really takes the teeth out of the statement doesn’t it? 

I’ve spent too much time over too many pints^* trying to figure out why the busy people are the way they are.  Poor time management?  Unrealistic estimates?  A need to feel more important than they are?  Guilt over their bill rate?  I finally realized that answering the question wasn’t productive, so I stopped thinking about it since I have a lot to do.

So stay productive and don’t get too busy too often.

*I said it was a choice, not a sin.