re:Supposedly, curry favor is from ME currayen favel with favel, fauvel being a fallow colored horse, which was a symbol of deceit, so, to be hypocritical.

and fallow colored as we know from the fallow thread, is a sort of yellow.

in the middle ages, beggers, lepers, jugglers, and marginalize peoples were required to wear striped clothing--very often yellow stripes.. and the devil in 'plays' was always shown wearing yellow stripes.. yellow has an interesting association with sin and deceit. stripes, and attitudes toward stripes in clothing have changed, but we still have the comic book assocication of prisioners wearing stripes... and stripes (broad, garish stripes) are still used on servants clothing.. (like doormen, or jockies, or McDoDo's employees)

of course, i still don't 'get' why to curry favor is.. has something to do with a chestnut.. (but don't bother trying to explain...)

more on stripes..
http://www.findarticles.com/cf_dls/m1134/10_110/80774396/p1/article.jhtml
(or you could read the book..)