I don't know exactly who said it. It could have been a protagonist who came to this realization after going through a series of challenges and learning lessons about the futility of revenge.
One reason it stands out is the detailed world-building and the unexpected turns in the plot. Also, the character development is really well done, making you root for the protagonist throughout the story.
I think 'Solo Leveling' has a great story. The concept of a weak hunter becoming the strongest is very appealing. The story is full of action - packed battles and the protagonist's growth journey is really inspiring. There are also various mysteries and political elements in the manhwa's world that add depth to the overall story.