There's been a few games I didn't expect to like that I eventually came to love, over the years.
World of Warcraft.
As crazy and counter-productive as it sounds.
When World of Warcraft launched, a few of my IRL friends played it and told me about it. From the way they explained it to me, it did NOT sound appealing. Not in the least. The whole idea of an MMO was a massive turnoff.
Then I got into Guild Wars when it first came out. It's kind of like an MMO gateway drug. I enjoyed the hell out of it while I quickly massacred my way to level 20 on a couple of characters over the course of a month or so. But once I had done that I started to get bored, and then started thinking about World of Warcraft.
A few OCR people had started playing WoW, so I picked it up and fell in love with it almost immediately. Three realms and four mains later... I've been playing for almost 8 years now. D:
Also,
The Legend of Zelda: Spirit Tracks.
I did not really care for Phantom Hourglass. Or any of the handheld Zelda games since Zelda 4, really. I wasn't expecting much from Spirit Tracks when I first played it. But I fell in love with the whole trains gimmick. Yes, it is a gimmick. But gimmicks aren't necessarily bad. It's not without its issues (there's a huge inconsistency in difficulty levels, especially later on in the game) but it's one of my favorite Zelda games now.
For that matter,
The Legend of Zelda: Majora's Mask.
I absolutely loved Ocarina of Time. Loved it. But for some reason, Majora's Mask... I despised its very existence. Everything about it rubbed me the wrong way. A direct sequel? Unheard of! It felt like Nintendo was just cashing in on the success of Nintendo 64. It felt forced. Even the commercials were trying too hard. I refused to play it for the longest time. Some years later, I bought a GameCube that came with the Zelda Collector's Edition disc, and after playing through Ocarina of Time yet again, decided to finally give it a try.
It didn't suck.
Last but not least,
Terranigma.
Looked like a super boring generic jRPG. Totally isn't.
Oh, and yes, as mentioned before in this thread, Frog Fractions. Brilliant.