Understanding the Concept of Leaving an Item on a Tree from Before Shabbos into Shabbos. Some Halachas About Using the Side of a Tree;
putting back a door that slipped off the track from a bookcase, wall unit, etc. putting back a knob that fell off a cabinet;
Many problems that arise in making egg salad, chopped liver, tuna fish, etc. (Besides the issue of LOSH).