Here is an Internet related pet peeve of mine.
When I fill out HTML Forms I tend to use the keyboard exclusively. This means I use TAB, and type in my selections normally. Well my Pet Peeve is that some companies put the entire list of world nations in alphabetical order except the United States. They tend to put that on top. This is just wrong. It screws up my flow and makes me reach for the mouse. Usually I just TAB into the field, type U and use the arrow keys to manuever.
What are some of your Internet Pet Peeves?