In Go, the ability to cast types is subject to specific rules. One important aspect discussed is the difference between casting `[]string` to `interface{}` and the inability to cast `[]string` to `[]interface{}`. The first cast is permitted because Go allows any slice to be assigned to an empty interface, as `interface{}` can hold values of any type. However, the second cast is inappropriate due to Go's type safety and the fact that slices are not interchangeable even if their underlying types are compatible. The reasons and implications behind this behavior are pivotal for Go developers, particularly when implementing data structures and interfaces in their code.