Is it ok to copy someone? If you are copying someone's work, it is not always bad. It might mean you don't want to become the master of something, so instead you chose to copy the masters. The time is limited and you can't master everything, that's why you prioritize to do other, more important things, than building an original website, writing a unique text or creating a special presentation. But don't just copy & paste the work of others and show it as yours, because what's done in the night appears in the day, — and others won't praise you for that. Instead, to make something relatively distinctive, look at the original for some time and try to notice the most important details, then replicate them in your work... Well, my point is not to teach you how to copy without getting caught, so let's move on.
If you are copying, you are missing all the experiments, all the trial and error of the author that brought them to this point — to the work that you see. And what does it take to become a master? Becoming a master, in my opinion, is finding your special way to do something, something that has never done before. It's similar to being the inventor. That's why nobody can teach you to become a master, you can only learn it by yourself.