What he really meant is there is nothing you can't do if you throw enough men at it. He learned that from ants. Sorry Alexander but we are sort of on our own here so it is harder. Throwing men or money at it won't work.
You don't, your memory does. During conscious thought you have a choice, but during unconscious as in dreams and nightmares they come from memory. But these too recycle back to memory to be used again. So you can not get rid of them unless you make a conscious effort to change them during conscious thought periods so what you want goes into memory to bury them. It works like this, during the day think about how work was and how it is over and you never have to do it again. Think how good it is now. (even if it isn't, lie if you must) Think anything positive all day because if you think negative it will reopen those bad thoughts again. Even if the negative you think during the day isn't about work, anything associated will find it in memory to haunt you. Negative breeds negative. Positive breeds positive. See how this works. So when something annoys you think about something more pleasant and leave the negative behind so you won't store any more in memory than that it happened. This is the difference between concern and worry too. Worry sets you up for nightmares by association. Worry doesn't even have to be about work only associated. EG a similar situation. Work comes up instead of the similar situation because there is more of it in memory. The object is to bury all those old feelings about work with some other pleasant thought. It works best if you can find something pleasant that happened around work. Enough positives and I can guarantee the night mares and sleepless nights will end. But you have to work at it.
Davit,
How do control this when you're sleeping?
Women, like men, should try to do the impossible
And when they fail, their failure should
be a challenge to others
Amelia Earhart
Visualization works well for nightmares. Basically when you have a night mare you visualize it as strong as you can make it the way you would like it instead of how you see it. In a short while that is what you will dream instead of the nightmare. Why it works isn't important, that it works is.
Man is so made that when anything fires
his soul, impossibilities vanish
Jean de la Fontaine
I found this a few nights ago. I had discovered a software programme which allows me to track my diet, and was so immersed, that I must have stayed for two hours, navigating it!