Do you frequently make a mistake while applying eyeliner and you end up drawing it thicker than you want it to be? I've lost count of the number of times! To make it (look) worse, I don't have much lid space to spare for rubbish like that. So for my everyday look, especially when I'm in a hurry, I resort to the demi-eyeliner (or half-eyeliner)
If you have hooded lids like mine, this style will give the part where they begin to droop down a little bit of lift.
***Demo on the right is done on a photo from another tutorial & the liner is a drawing, not a real eyeliner =D