mosherose – excuse me you can’t be so quick to pass judgment. it’s obvious that you’re not involved in the kitchen (which is totally fine) however, YOU try to figure out which kid won’t be in the mood of chicken this week, and which one will finish off 3 pieces of potato kugel. Sorry, people are unpredictable, sometimes they eat way more than you expected and sometimes the opposite. You also don’t want to be stingy and prepare EXACT amounts so that people won’t feel comfortable taking more.
There is nothing wrong with leftovers, the idea with the man in the midbar (whether you were joking or not) really falls into the catogory of Emuna, of living day by day and not worrying about the future.