Me, my girlfriend, my mom and my dad all have PCs bought from a shop. That makes you a liar since we have our rigs bought as one piece and therefore you can't have yours built by yourself.
*actually built them all
This isn't about people wanting or not wanting to wait.
It's all about the immersion the game can provide. Our brains are used to "no delay", simply put - your brain tells your hand to move, it does so instantly. Given that the keyboard and the hotkey system is there to emulate those brain links, any delay breaks the immersion. You don't tell yourself "I'm going to push number 1 where my main attack ability is", but rather "I want to attack". When there is no delay, or to be more accurate - no noticeable delay, your brain accepts the control system and focuses more on what's happening on the screen. The game immersion raises to the point where you might not notice your surroundings.
The delay brings up the feeling that you aren't actually controlling the character, but rather fighting the interface.
Every millisecond above the "unnoticeable" delay (which varies from person to person) break this immersion and makes you realize you are sitting in your chair pushing buttons. This can be very frustrating since most players go to games to relax and rest.
Given my psychological education I understand this concern rather well and know why the character responsiveness is nr. 1 topic for Bioware and why some people can't enjoy the game when experiencing the delay.
To give a real life example (while it might be a bit crazy, works for the purpose) - Imagine you are in a car with your friend who is driving, you are sitting at the passenger's seat. Now your friend isn't allowed to drive, but he can only do what you tell him to by simple instructions, such as "turn the wheel left", "chance the gear up", "left indicator now", ect. And you aren't allowed to queue these instructions up ("drive at the end of the next block"). My personal guess is you won't be able to enjoy a thing from the passenger's seat and it will be very stressful transporting experience.