Knuckles is lonely.
Sure he has the Master Emerald.
Sure he is the last of his race, or was at one point?
Like that kind of pressure gets to you.
Also he has carpal tunnel because his wrists cannot hold his hands up.
That is one terrible genetic defect.
What if Knuckles wants to drive a car?
What if Knuckles wants to learn guitar?
Too bad.
Knuckles is lonely.