1. The user is an idiot

The user is not an expert. My doc doesn't require me to know the difference between low-density and high-density lipoproteions. 

Don't assume user should know what kind of browser they use or what is the best flow to use the app. 

But yes, no matter how much you think of it, sometimes the user demand feature that seem pointless and he can have difficulties with functions that seem to be self-explanatory.