The closest for me I guess was when I was younger, and the MLP website changed from G3, to G4.
At first, I thought "Omg these ponies look so skinny! I want the other one back!" And I thought they looked kinda weird. I was young okay? Wasn't too crazy on the logo either.
One day, I watched the first episode, and liked it.
And now, today, I love how the ponies look and I love the show and everything. I don't really understand WHY I thought it looked ugly.