As a child I used to love plushy toys, now not as much.
I used to really love waking up in the morning, now I don't even see the morning, I sleep right through it.
I used to like to play with bugs; I can't believe I used to touch bugs it's really gross to me now.
I used to love gymnastics, now I hate it.
Opposite of what you asked:
As a kid I hated piano, now I love it
When I was a child i always wanted to be a artist, now I'm into veterinarian stuff (well since 3rd grade anyway)
I used to hate bananas and now I love them.