Rebecca, I'm going to put this as nicely and thoughtfully as I can, with as much caring and compassion as i can muster.....Rebecca, your a freak.
You are a text book example of someone suffering Obssesive Compulsive Dissorder
http://wik.ed.uiuc.edu/index.php/Obsess ... _Dissorder
OCD is manifested in a variety of forms, but is most commonly characterized by a subject's obsessive drive to perform a particular task or set of tasks
You took a project management book with you on holiday, who in their right mind would need to form a Business Case and produce a PID as to whether they should stop for lunch or not en route to Andalucia
One thing that did bounce around my noggin was, maybe the reason the "read emails", "tidy sock draw" etc gets done first and ticked first is because they are easy, they are predictable, they are known quantities, you have a far lower chance of failure with those so can quickly put lines through things in the list. Doing something creative like "come up with xyz for section abc" means exactly that, come up with something random, yet associated, its an unknown, being creative is harder than repeating what you know and has a much higher chance of failure than "tidy sock draw", and requires more effort just to get a line crossed off the list.
Also, you add lines in for thing's you've alread done, hence again pointing to a need to cross of the line, but its the crossing off of the line which seems to be of most importance, not the gravity/scope of the task.
So, to fit in with your change of strategy, how about changing the length of the line and thickness of pen for the items which are more important, difficult, lower chance of success etc. That way, you still get to cross things off, but the reward of a few big fat massive lines outweighs the little ones......oh wait, maybe I meant that speach for Kate Moss
Thus endith the pointless patronising drivel,