Controversial: I like pineapple on pizza.
1st- it tastes good, and is not a disgrace to Italians since they didn't create pizza.
2nd- society tells you to hate it, which only influences my love for it. It's like when your parents/teacher tells you strictly to do one thing. Of COURSE you'd want to do the exact opposite!
3rd- there's other fruits on pizza: tomato, banana peppers, etc.
4th- it tastes good. The fruit pairs well with the ham.
5th- pineapple has a tingy, almost carnivorous sensation when you take a bite. I like to live life a little on the edge, even if it makes my tongue feel weird for the rest of the day.
Conclusion: don't let society change your stance on something as simple as a pizza topping. If you truly like something, you shouldn't be ashamed about it, it's personal preference, not fact. I've seen literal fallouts in relationships/friendships over something as trivial as this. Don't be like that. Please.