Leaving bread at the end of a meal

Hi,

We are taught to leave a little bit of bread at the end of our meals, for two reasons: (1) for a needy person to come take it, or (2) because in birkat hamazon we ask for G-d to bring blessing upon our table, and that requires that there be something present, to be blessed. [This is brought in Shulchan Aruch Orach Chaim 180:2.]

One who eats in a commercial setting, such as a workplace cafeteria, need not leave anything; it is not likely that a needy person would come take it, and the food will simply be thrown out.

(Rivivot Ephraim 1:135)

המצפה לישועה,
Mordechai