I caught a colleague googling google so she could then use google to search the web. I explained she could just type directly in the search box (labeled google) to find stuff.
At the school I go to, my teacher does this. he says its easier for him (I've seen him google yahoo before, and vice-versa too)
Makes me want to scream at times.
One of my biggest is people who think that because you help them once you are their dedicated IT staff.
And one in general is people who think they know everything, and will fight that they are right, even after you have pointed out their error. I go to school with a kid like this, makes me want to rip my hair out.