When I spill my coffee while reaching for my coffee to move it so that it won't get spilled. When my printer or fax runs out of ink on page 9 of 10. Of course, this always happens when I need the print in the next five minutes and I'm out of new cartridges. When I don't notice the empty TP roll until you know when! When I drive into to town [15 minutes each way] at 12 AM, for Nyquil or something that I really have to have, and I forget my wallet.