Is the Universe Like That?

We define inertia as the observation that whenever you have an object, which is mostly energy or whenever you have a lot of energy in one spot in one kind of thing, it's kind of hard to make that thing move. And so that observation, that's what we call inertia. The big question is like, why is that? Why is the universe like that? Well, like why is it hard to change the velocity of things that have a lots of energy? That's a great question. I think it's important when we ask big questions like that to think about what kind of answer are we looking for? Like there is no way to build another theory of physics that doesn't have