In fact, the "Crazy" part of the trope name Crazy Cat Lady is Truth in Television because a parasitical disease Toxoplasmosis that causes neurological maladies such as schizophrenia is commonly found in litter boxes of many warm blooded animals (especially prominent with cats).
Thus adopting more pets than one can maintain a clean healthy standard for increases the chances of the owner becoming this trope.
You’d better love (or at least tolerate) cats, not be allergic (or pop Benadryl), and brace yourself for cute cat pics and anecdotes galore.
“You can’t be as spontaneous with a dog woman," he explained. He seemed smart and unusually self-aware for a 31-year-old guy, and his social skills were off the chain.