Do you really mean what you say?
" She chickened out at the last minute."
" Sheila and Joe can be very foxy."
" He made an ass of himself in front of everyone."
Words and expressions that we select for us in everyday conversation can be descriptive, powerful and unintentionally hurtful all at the same time.
Each one of the examples above serves to describe human behaviour in a negative manner. However when we stop to consider the complete effect that each example makes, we can see that it is degrading as well to the animals being used to metaphorically in each expression. In reality, the behaviour of any being is too complex to be reduced to a single, negative characteristic. The movement of a chicken , the agility of a fox, the comportment of a donkey, each occurs in a specific context and for a very specific reason.
Next time you want to describe a person's behaviour think twice before you speak. Then, when you do so make certain that you are not sacrificing the integrity of a fellow creature.
One of my favourite things was to call everybody a "Jackass" at times, but ever since my love of donkeys has grown I try very hard not to use this term in respect to the animal it depicts.