I found collecting every Triple Triad card in FFVIII challanging but addictive. I even started a new game just to get the Angelo card. The Card Queen part of the subquest is clearly the most annoying, but getting the rare cards makes it worth it.

While chocobo racing in FFVII itself was fun, breeding and feeding nuts and greens to chocobos was really annoying. Especially trying to breed a blue/green couple. After getting a green female, I was so ecstatic over finally getting a blue male after a gazillion tries I named him 'Lucky'.

I don't do the clock puzzle in FFVI until I get Mog and the Moogle charm. And with the Tomb of the Nameless King and Odin subquests in FFVIII I use Enc-None. I hate puzzle-solving and fighting at the same time.