Learning something new.
Learning new things is easy. All you need to do is to expose yourself to whatever it is you want to learn enough, try it our for yourself and then you’re done.
Mastering new things on the other hand, takes time. It might still be easy, but it will take time. When you’re mastering something, you need to take in a lot more than the basic information needed to understand. You need to be able to explain whatever you’re learning and you’ll need to be able to apply it in contexts other than the ones you’re used to and most importantly.
The notion of it being hard to learn something new just isn’t true. It all depends on the level you want to be on for the task.