When you rub your eye but you forget you're wearing eyeliner
Don't you hate when this happens? That's why I only use smudge-free eyeliner. You would have to dip my entire head in alcohol before my eyeliner budges.
My personal fave eyeliners are:
CoverGirl Bombshell Intensity Liner
Make Up For Ever Aqua Liner
Kat Von D Tattoo Liner
Maybelline Master Precise Skinny Eyeliner
Love these, they never smudge!