This may sound funny, and cut me off if you find this boring/irritating/pointless... but I'm trying to get a handle on something in particular.
Let's say that you were going on a picnic - just you and one other person. Standing in the kitchen, you are going to make sandwhiches. With no idea how hungry or what the other person wants or likes, what kind of sandwhiches do you make and how many? How do you make that determination?
Sitting at a table, you are drawing away, really into your work. All of a sudden, assuming you are using a mechanical pencil (can replace with paint or ink :P) and distractedly, you fill the pencil up with lead. Except this time, without noticing it, you were able to fill it up without any problems and continue on. Would this happen? Is the common situation where you needed to fill up the pencil with lead difficult for you?