I had a probable workaholic in my team a few years ago. He would come in early. He would stay late. And he would come in when he was on leave. As in, every day that he was on leave. The LCol we worked for got wind of this, and had the commissionaires deactivate his building pass the next time he went on annual leave. It was a message -- an intentional message to the entire unit -- that he should get a life. And that we all should have lives and hobbies -- wives, kids, motorcycles, horses, golf, XBox, he didn't care what we were doing, but he wanted us to have lives outside of our jobs.
If what you are doing is so frigging important to your unit that you can't be spared for a few days at a time to go on leave -- then what happens to your unit when you break your leg, or get sick? There has to be some redundancy -- everyone is replaceable. For those in command positions, isn't one of the great functions of leave to allow your 2IC to run the shop for a while? And if the commander never takes a break, aren't you setting the example to your juniors that vacations are for wimps, and if they want to succeed, they should also be working through leave?
For those of you that are doing work while on leave -- I respectfully suggest that you might want to prioritize your tasks, drop the ones that no one really cares about, and find yourself a hobby. I hear that the kids like Warcraft.