Ok, at home, my parents and my sisters are really kind and they don't do noise. Also my mother understand that I need some concentration when i'm on computer, although she don't know what the benefits of 'sitting for long hours in front of a screen with much gadgets and text!!'

The worst time is at school, when my friends (tech-savvy people) ask me for questions in a very noisy way that I loose concentration. So I agree with most of you about concentration, we can class it then

Concentration

Computer bugs and speed

Screen (if u sit for long hours)

Mouse and Keyboard (especially for those cheap laser mouses!!!)

Computer noise (if it's an old dirty one)

your girl friend (if u got one!!!)

Those are all factors that can affect your programming or whatever you are doing if it's mind related, like Math or Physic calculations

Also I posted it in SOF, no the question was not closed