The need or desire to use the same towel each time after showering. This may be a favorite towel with sentimental value, or the beach sized one that covers all your parts. This condition is frequently only suffered by one member of a family, causing much frustration upon finding that someone else has used "your" towel.
Boy: "Mom, where's my green towel?"
Mom: "It's in the wash, hon. I used it to dry off the dog earlier."
Boy: "Damn you, towel permanence. Now I cant shower."