  Theophrastus, who gives us the most thorough report of Democritus' theory, criticizes it for raising the expectation that the same kinds of atoms would always cause similar appearances.  However, it may be that most explanations are directed towards the normal case of a typical observer, and that a different account is given as to the perceptions of a nontypical observer, such as someone who is ill.  Democritus' account why honey sometimes tastes bitter to people who are ill depends on two factors, neither of which undercut the notion that certain atomic shapes regularly affect us in a given way. One is that a given substance like honey is not quite homogeneous, but contains atoms of different shapes.  While it takes its normal character from the predominant type of atom present, there are other atom-types present within.  The other is that our sense-organs need to be suitably harmonized to admit a given atom-type, and the disposition of our passageways can be affected by illness or other conditions. Thus someone who is ill may become unusually receptive to an atom-type that is only a small part of honey's overall constitution.  