sheets that slip off the mattress

you ever been sleeping on a bed, and the sheet decides to slip off while you're asleep and part of your body is touching just straight mattress. there is no equal feeling in the world. it just feels horrible. and to make it worse you know that you have to wake up and get out of bed if you're going to want to fix it, rendering you wide awake. or how about when you have a pillow thats too big for the pillowcase and likes to slowly slip out of the case over the course of a few days.