Rosario + Vampire - I don't like Harem manga in general and probably wouldn't have gone anywhere near it, had my Cousin (who generally likes the same sorts of shows as me) recommended it to me. She was also the one who told me the manga was very different from the anime, so I switched to that when I didn't like the anime and I haven't looked back ever since.
Yu-Gi-Oh 5Ds - Because card games on motorcycles seemed too goofy to me. Eventually though I gave it a chance, got hooked five episodes in and binged the first couple seasons in a couple days. There's also ZEXAL to a lesser extent, but 5Ds and "something else" had already taught me not to pay attention to the hate and to make up my own mind about it.
Digimon Savers - Meet the something else. Hearing about the goofiness of the main character punching Digimon put me off watching it. Eventually though, I bit the bullet and thank God I did because Savers was fucking awesome. Easily the 2nd best season of the show, ONLY beaten by Tamers.