Tell me something important about IT that I don't know

I am a geek, I have learned so many Techlonogy, But I still think there is something important that I don't know. So try tell me something important that I don't know.

It should be related to IT, here is part of what I have studied:

hardware: Digital and Analog Electricit | PCB | FPGA | DSP | MCU | CPU-architecture

software: compiler | LLVM | operating system | linux | cloud-computing | Virtualization | Container

language: verilog/systemC | C/C++ | Python | java | javascript | haskell | lisp | function-language | logic-language | ... (needn't recommand anymore, It's enough)

web : front-end | back-end | react | spring | nodejs | koa | ... (needn't recommand anymore, It's enough)

other : algorithm | design patterns | software engineering | Artificial intelligence | big-data | Continuous integration | devops