“You can’t go to the zoo if you are pregnant because you can only look at beautiful things. “
This is a great example of why we must keep mesorah, whether it makes sense or not!!
The actual saying, minhag, whatever you want to call it is, you shouldn’t look at animals, while pregnant. many seforim bring it down.
(Bronx zoo, Bronx ppl looking at zoo while pregnant, you get the picture)
now imagine someone said you should only look at pretty things, you’ll say they’re nuts, and go to the zoo. In reality the person was correct we shouldn’t go to the zoo, but the reasoning was incorrect. lesson learnt stick to mesorah, whether you understand it or not.