Killua, didn't like nature. He didn't like plants, he didn't like animals, he didn't like bugs. He didn't like fish, or being outside in general. He was 5 years old, and hated nature and its entirety. This frustrated the Zoldycks, as they literally lived in a particularly forested area. Their family was wealthy and owned a decent sized mansion as well as a lot of property, which happened to be mostly forests and there was a beautiful lake. His family loved their property, and the nature. Killua though? He hated it.