Why It’s Hard To Learn Similar Things When Learning A New Language

I find it easier to learn things that are different from each other in a new language. Take colours for example. If I can space the colours or connect them to something else, like a plant or a shirt, and I come across them in different situations, then eventually I assimilate them. I start to learn them. But if I try to learn them as a list, I find that very difficult to do.