Most of the time these people will actually make up complete nonsense story to justify the pet behaviour, including completely stupid stuff like "it's Tuesday, he always like to be on the dinning table on tuesday" and endless other nonsense.
There are several papers [ Example: http://blogs.scientificamerican.com/science-sushi/toxoplasma... ] describe how Toxoplasmosis could not only get into owner's system, but also change their behaviour; they had demonstrated that mices infected with it would actually be /attracted/ to cats completely irrationally.
When you look at this and extrapolate on how many people are actually /crazy/ about cats [ Check, the interweb! ] and could be affected by that sort of brain damage --all of them driving, voting and making 'rational' decisions-- it's really worrying...