if you work in IT then you have to know everything about
3- Programming (system, web, .. etc).
4- Hardware (know how to fix all hardware issues).
5- Know all applications in the world.
6- You have to be an expert in Ms Office specifically.
7- Mobiles, basically any tech device.
8- the list goes on ..
basically you can't say I don't know, you have to have an answer for every question asked by the user ... if you said I don't know, you're not qualified ...