What is the hardest thing in coding world?

Hardest thing in coding is when you become frustrated that you can't build something, but that feeling of frustration comes because you are trying to use something in the language that you don't understand. When you don't understand something, it means that you don't fully understand something that is more basic, more foundational, than what you are trying to do, and if you find your self feeling frustrated repeatedly over time, like a cycle of this frustration occurring, it means you are not honestly trying to learn properly from the ground up. It means you are being lazy, and are self deluding yourself into thinking you know what you're doing when you really don't. So beware of the feeling of frustration when trying to code. That's what that feeling means if you experience it, and the way to beat it is to be honest with yourself and train yourself to learn properly.