When you’re making a detailed list, column headers are extremely important. It’s possible to do without them, but after four columns or so I usually find myself studying the contents and saying “Now, WHAT did this column contain?
Likewise, when making a column of formulas it’s extremely helpful to have named the column(s) that the formula refers to. It can turn the formula =b1*c1*d1, which could be anything, into =height*width*depth, which is pretty obviously the formula for the volume of something. Plus, if you have a long and complicated formula, it makes it harder to make accidental mistakes. Plus, it’s a little bit harder to spot the problem in =(b1-c1)/a1 than it is in =(value2011-value2010)/value2009 when trying to calculate the annual percentage change in something. [The correct formula would be (value2011-value2010)/value2010, or (CurrentYear-PreviousYear)/PreviousYear.]