Quoted from LyonsRonnie1:

The other day I was ordering some stuff from Marco (which I love) and had written down everything I found on a machine that I needed to order. So while I'm doing it, I see something I hadn't thought of like, oh instruction cards and add that to the cart too. So then I go back to the machine, work on it awhile looking for other stuff I might need to order, oh, I need some of those clips (or whatever)... so I go back to add it to the cart off the website, and the cart is empty because I screwed around too long without checking out.
Damn, now I'll have to redo it all over again. So I go reorder everything I had written down, then add the clips and checkout... then just after I press the checkout button, remember that I forgot to add those cool instruction cards (for $1.50 or whatever) back in