It doesn't matter how many times you've been told "Always make sure you have everything necessary before you settle down and start working,"because time after time, you will sit down, spread your work before you, grab a mouse/writing utensil and just as you're ready to be productive, you suddenly realize:

A)  If you are using some electronic device, especially that of a public school lab, you aren't sitting at the right station, either because your computer doesn't have the right software or because it doesn't have the right operating system.

B)  You accidentally left some needed materials elsewhere and now you're much too lazy to get it.

So, for the umpteenth time, make sure you have all the things you need before you lose that "focus mode"!