I don't deal well with stressful situations or loud noises, especially repetitive ones which kids seem to specialize in. Also I think the societal expectation that all women should looooove children rubs me the wrong way so I tend to overreact so people won't throw their baby into my arms or talk to me endlessly about their kids. I'm also admittedly spiteful that the large majority of my friends turn into boring, passionless zombies after having children and many seem to give up on living their lives so that their children can live theirs. It's fine and their decision, but it depresses me that my friends are "stolen away" and I blame their kids for it.

That said, I hate bad parents much more than children. A polite kid can be quite nice to interact with.