In Moed Qatan 27a, the gemara refers to a certain type of couch or stool as an ערסא דגדא: a couch of fortune. Rashi explains it as a couch that is only used for showcasing mazal tovs:
מטה שמייחדים אותה למזל טוב ואין משתמשין בה כלום אלא מייחדין אותה לשרות מזל טוב עליה
"A couch that is designated for a mazal tov. It is not used at all, save that it is designated for the placement of a mazal tov upon it."
What is this mazal tov to which Rashi is referring? A good luck charm?
Rav Yosef Viener explains the mazal Tov of such a couch is that when you have a feeling of having everything you need and then a little extra chesed too (like a couch which you dont use or the "extra" birth of Gad--see rashi on the pasuk) living without showing you need to squeeze every penny, that itself is a good mazal and will activate more good mazal of bracha. The opposite is true also, where feeling down and pressed can bring a mazal Ra r"l and the negative side effects with it.
