How the hell did this character become unlikable? 
 
When the the Sonic Sucks Bandwagon tour got kicked started after the released of Sonic Adventure 2, then ended after the the release of Sonic Colors, people hated everything about Sonic (that includes the 2D games) because they didn't like the past 3D games. 
 
Now when I say that they hate everything, I also mean the characters. Sure, some of those characters' designs are ridiculous, and when they make they're appearance in a Sonic game I feel like they were just shoehorned in. Every character in the series got so much hate, including Knuckles. Really? I get the feeling people just hated Knuckles because he's a Sonic character, that's all.
 
I thought Knuckles was a likable character when he first made his debut in Sonic 3. I also thought he had a excellent design and a likable personally - he's a badass, cocky, and kind of mischievous in the genesis games. I will admit, I disliked what Sega did to the character after Sonic Adventure making him all serious and partially nothing like his genesis counterpart. And those fucking scavenger hunt levels, just give me some regular platforming levels with some nice beat em' up action with Knuckles still pimping the slutty bat girl. Okay, maybe Sega did one good thing with Knuckles in the 3D games.
 
Though I feel like Sega give the character a bit of redemption in Sonic Generations. I liked how Knuckles was betray in that game. One of his lines is: "Thanks for the help, not that I didn't needed it," that felt like the original Knuckles. Maybe there's hope for the old Knuckles to come back? 
 
Also, I like the Knuckles rap themes >_>
  

People just get angry because they associate Sonic side characters with bad games because 5/6 of the characters in Sonic Adventure weren't Sonic, and 2/3 of them in SA2 didn't play like Sonic (because the Shadow levels were the same design wise).

Knuckles is fine. I still like Shadow as a character, and I have an ironic appreciation of Big the Cat. And, of course, Dr. Robotnik is classic.

The rest can burn in hell, for all I care.

I used to really like Knuckles as a kid. I'm not sure why now though.

His hair grosses me out.

Knuckles is alright. I guess least terrible would be a good way to explain it?

 I have an ironic appreciation of Big the Cat.

I don't like him simply because he wears a cowboy hat for no discernible reason.

As far as angry looking rival characters, that have been introduced in every other Sonic game since, go he is pretty alright.

I think Knuckles is a pretty cool echidna. Eh protects Chaos Emeralds and doesn't afraid of anything.

I'm with you on Knuckles, although my sole exposure to him for many years was in Sonic 3 & Knuckles. He adds a really cool three-way-conflict dynamic to that game, acting as neither a friend, nor an out-right antagonist - sure, he doesn't want you to get your greasy hedgehog mitts on the Chaos Emeralds, but he's just as opposed to Robotnik handling them. He also controls pretty distinctly from Sonic, on account of his wall-climbing and gliding skills. I guess that's why I appreciate him as a character. Having no experience with any recent Sonic titles besides Heroes (if that can really be considered 'recent' at this point), I can't really offer any other commentary on him. All I can say is that when I think of Sonic, I think of Sonic, Tails and Knuckles as the established anthropomorphic power-trio of that franchise.

I don't think a lot of people stopped hating Sonic after Sonic Colors. If anything all it did was make people who already loved Sonic hopeful about the series' future.

Knuckles im still cool with and everything and i still like sonic games and everything (i understand im probaly going to get a huge batch of WHY? for saying epscailly for the fact ill say the non wii version of unleashed and loved colors Except for sonic 06 that can piss off and die in hell for all i care) Knuckles got very cocky again there and such in generations so can still be as he is also now amy....amy just needs to get the hell out and never return and plus knuckles got his own fucking game look it up Knuckles Chaotix