I have told the wife that if she ever brought a cat home that I would be moving out. Here is why.
When my Dad was in Vietnam, another serviceman down the street was also in Nam. The wife went to Hawaii for R&R with him, and had my grandmother, who was staying with us while my Dad was away, watch her children.
She agreed to do this before seeing the inside of the house. They had a number of cats, and their excrement (any other word will get me in trouble here) was everywhere. My grandmother had me help her clean up, and it was a nasty, stinking mess. I don't think any of those cats was litter trained, and they were all consigned by us to the garage.
Two days after the woman left, her youngest, 18 months old, became very sick. He soon ended up in the hospital, and even though my grandmother tried to get in contact with the family, she received no response. Even the Red Cross had trouble getting in touch with them.
The woman returned, one day after her child died in the hospital, probably from the foul conditions in that house. An investigation was made by the authorities, and fortunately my grandmother was quickly cleared, even though the woman had some explaining to do. She also refused to pay my grandmother what she had agreed to, but she just wanted to be done with that family.
Yes, it was probably a case of bad owners rather than bad cats, but something like that made an impression on my young teenage self. As a result, I have no use for cats, now more than 50 years on.