Some games are so bad, I have to actually use the mouse to target enemies, and I hate having to do that...
Why Mr. Englebart, why do they hate you?
It simply stems from the fact I've been playing MMOs for over 10 years, and that I have played them, for the most part, with both hands on the keyboard.
Because chatting (text-based) has always been my favoured way to communicating in those games, and that I am used to typing with both hands, it means I often find myself playing without any hand on the mouse. Hitting tab with my left hand's pinky or hitting "0" on the keypad with my right hand's thumb is a lot more energy efficient than moving my arm to my mouse, locate my cursor on screen, move it around to the target I want to pick, and clicking it, then putting my right hand back over the right-hand side of the keyboard.
I don't hate mouse, I hate the mix of chatting and mouse-based controls. It's the same way I hate using a gamepad in PSO/PSU/PSO2 and in FFXI/FFXIV: It's way too much of a pain to put my controller down, set both hands on the keyboard to chat, then grab my controller back.
I assume that if I was a VoIP user, I wouldn't have any of these worries.
Alas, I hate VoIP, so I have to deal with tab targetting.