The nature of problems connected with binding which arise in the everyday work of experimental physicists and material scientists is illustrated by reference to two different experimental studies. (i) Sliding in crystals of group V elements is found to take place not only along planes cutting the quasimetallic bonds, but also along planes apparently cutting their "covalent" bonds, thus suggesting that a more elaborate picture of the two types of bonds and of their interrelation is necessary. (ii) The physisorption of linear pentatriacontane on alkali chlorides indicates alignment of the paraffin molecules along the [ 1 101 directions. This may be associated with polarization of methylene groups by ions in the substrate. This hypothesis must be substantiated by suitable quantum-theoretical calculations, which in turn must be based on an adequate description of the adsorption bond.