This is going off the point a bit, but I saw on a documentary that cats rub their heads against your ankles and walk around your feet because they have glands by their whiskers that secrete a hormone/ scent onto so that the cat can't lose you. Isn't that sweet? My cat usualy follows me because he a) hungry, or b) my neice is terrorising him! :)
Mine follow me around all day, and not for food. Cats like companionship regardless of what is said about them being aloof and independent. Would quite like to go to the loo though without them all waiting outside the door!
Well thats easy! He/She wants a bit of love and attention.
Or your cat is a little greedy and wants a little (when i say little i mean big in the cats eyes!) snak!