Every-day pedestrian computer tasks should be easy to complete with the keyboard only. Mice were bad enough as a crutch for lazy users, but now it's a crutch for lazy developers.

Let me pick on Mozilla for a second. In many of Firefox's menus, they have alt keys. You know, an underlined letter in a word that you can select by holding the alt key and pressing that letter. In FF, many of these letters are capitalized. So now you have to press shift+alt+whatever letter. Criminally bad design.