I have the reoccurring one of milking cows.  We end up buying about 3 or 4 cows to have something to do in the winter that are to be sold come spring, before we know it we are back to 100 cows and decide to keep them.  End up buying back all the milking equipment and fixing the barn back into a barn and taking out the kitchen and office area.  Usually have this dream two or three times a year.  I consider it a nightmare.