Microsoft Windows and applications shortcut keys.
When I just start working as a web programmer, I was always amaze that programmers use shortcut keys to control the PC. Which I didn't know that is possible when i was in college. What I learn 1st was the Ctrl+S, Ctrl+V, WINKEY + D when I was doing my training in Singapore.
Later, when I formally work as a web programmer in KL, I notice alot programmer like short cut keys. Unlike normal user only use mouse. Learn more tat time.Which I think its fun~ Easy~ interesting.