It's no secret that Goku loves to fight, as shown throughout the course of his Dragon Ball career, and he even gets increasingly more excited when he is fighting a particularly strong opponent because of the implications that he will get stronger as a result. However, there are two exceptions to this perceived truth about Goku and, as it seemingly stands in Dragon Ball continuity, these exceptions are the only two types of fights Goku actually hates.
Goku was introduced in Dragon Ball chapter 1 by Akira Toriyama and right from the start, readers are explicitly shown how much he loves fighting. In the early days, Goku was mostly battling dangerous wildlife to kill and eat them, but the enjoyment behind the act of the battle itself was readily apparent and only increased as the story progressed. Before long, Goku was participating in tournaments, taking down world-wide fascist regimes, and even defeating the most powerful villain on Earth at that time. The biggest similarity between all of those battles was the fact that Goku loved every second of them. That is, until Goku got an intergalactic slap in the face by his long-lost brother, Raditz.
In Dragon Ball chapter 200 by Akira Toriyama, Piccolo and Goku team up for the first time to defeat Raditz, a space-traveling world conqueror who kidnapped Gohan in an attempt to coerce Goku into joining his team of intergalactic villains. Instead, Goku and Piccolo–who only joins Goku because Raditz is a major threat to his own schemes of world-domination (or so he says)–take the fight to Raditz and attempt to kill the evil Saiyan and retrieve Gohan. At this point, Piccolo and Goku are no strangers as Goku killed Piccolo in his past life and defeated the current Piccolo in a World Martial Arts Tournament. So, Piccolo is very familiar with how excited Goku can get in the face of a challenging battle. Before the fighting begins, Piccolo even says to Goku, “You must be pretty excited, huh, Son Goku?” Goku replies, “Sorry but this time I ain’t all that excited,” Goku then continues by saying, “I’m so scared, I’m trembling!”
If there is one thing Goku doesn’t know, it’s fear. This is proven true with how flippant he is in his actions upon meeting Grand Zeno in Dragon Ball Super, a being with the power to blink entire realities out of existence with a mere thought. But in this chapter, Goku is frightened, and it is clear that it is because he is worried about the life of his son, Gohan. This tells fans that when Gohan or presumably someone he really loves is in danger, Goku hates fighting because he is too worried about their safety, which is a bit different from the other type of fight Goku hates participating in. In Dragon Ball Super’s Resurrection ‘F’ storyline, Goku is once again fighting the villainous Frieza who has returned from the grave to kill Goku and destroy Planet Earth. Rather than being happy at the prospect of fighting an old villain who has gotten much stronger since their last bout, Goku tells Frieza that he is disgusted by how evil he is, making their battle totally unenjoyable.
Even though Goku doesn’t care about the potentially catastrophic implications of a certain fight so long as it helps him increase his power level–with Dragon Ball Super’s Tournament of Power being the greatest example–it seems there is a limit to Goku’s desire for battle. But, if the life of someone he loves, most notably Gohan, is in clear and apparent danger or if he’s fighting someone who is just pure evil, Goku would rather not fight at all, confirming the two types of Dragon Ball fights Goku actually hates.