The size of the Sonic fandom.

My favorite character is Tails. Where else are you going to find someone who is simultaniously lancer, brains, and child appeal all at once? I loved him when I first saw my older brothers play Sonic the Hedgehog 2, I loved him in Sat AM (marginalized though he was), and, more than a decade later, I still haven't stopped liking him.

Heck, I stayed clear of Sonic Underground largely because of its lack of Tails.

My favorite character is Knuckles, he is Sonic's perfect rival, though Shadow has replaced him as Sonic's rival, I think Knuckles is much more worthy of that 'job'.

Why I like him? I have no clue, I just like him.

Knuckles was fun because even though he was fighting you, you could tell that he had a good cause (he just believed the lies Robotnik spread about you which, since almost every incarnation of Robotnik was rather charismatic, was somewhat plausible). Playing as Knuckles was also cool.

I love Knuckles for that reason too. Still think he needs to spin off into his own series so they can stop trying to make up excuses to involve him in Sonic titles, though.