Being evil, Trying to take over the world, cheating people, being a jerk to his minions, annoying Sonic, creating robots, His grandfather Gerald Robotnik
Sonic and his friends, his plans failing, other villains going too far
Dr. Ivo Robotnik (better known as Dr. Eggman) is a mad scientist who has terrorized the residents of Sonic's homeworld. He got all of the Chaos Emeralds and had everyone transported to Earth. While on Earth, he tries to take over but is constantly foiled by Sonic and his friends.
Eggman is your typical mad scientist. He strives to take over the world and beat the heroes at all costs, he loves gloating about being evil, he loudly voices his schemes and is highly arrogant and overconfident. He's also very goofy and loves rambling.
Despite having the IQ of 300 and being brilliant at inventions, Eggman is terrible at scheming and never thinks his evil plans through, hence is the main reason why he loses to Sonic and his friends over and over again.
Despite being the villain, Eggman also has a sense of sentimentality. Though he'll mock and threaten his victims with no problem, but he does not like hurting them. Also, though his goal is to rule the world, he does not like the idea of destroying planets, explaining why he's against the Metarex. He does also have a sense of understanding. Like when Chris blamed him for something that he was not apart of, Eggman lectured him that blaming people is wrong and he will end up hurting his friends if he keeps it up which in fact made Chris realise it. He also stopped Sonic from going dark against Black Narcissus. Eggman also loved his grandfather Professor Gerald Robotnik deeply and views him as a childhood hero. He was also quite upset to discover that he would attempt to destroy the world.
Though he's furious at Sonic for constantly stopping his plans, Eggman does have some respect for him and will work with him against larger threats than himself, like the Metarex.