Though it's after Sonic has spent time with Tom that the former started wondering if Longclaw was wrong and if it is possible for him to live peacefully with other people even with his powers.
Also, Robotnik hates Sonic, while Tails idolizes him.
Once the games are over, Sonic is there to help cut the cake and serve it to guests.
And it was because of them seemingly killing Sonic's mentor Longclaw that Sonic had to go to Earth.
In the movie, Knuckles is a fearsome physical threat and clearly outclasses Sonic during their original fight.
Scourge The Hedgehog, the Sol Emeralds, and the events on Mobius are the best examples of why the Chaos Force overall is a powerful one to control.