Consideration of meso-compounds constitues an important part of fundamental teaching about stereoisomerism at university. These compounds show both chiral and achiral conformations but are typically inactive in a polarimeter and should be seen as good examples od microscopic-macroscopic duality in stereochemistry.
Pressure and restraints of teaching (curriculum, time...) lead however a majority of teachers to be careless about the confrontation between a lonely molecule and a great collection of molecules. It is only in cyclohexanic serie that this confrontation is usually taken into account.
Some propositions are advanced in order to avoid, as much as possible, a too dogmatic teaching display in order to prevent mistakes or misunderstanding of students.