"Folks with glossy facades cannot keep their fake veneers on for
long... sooner or later, the cracks and blemishes will show."
Ah, or this one...
"A rose that looks perfect at the crack of dawn might look
different under the harsh glare of the noonday sun."
Hmm... how many different and creative ways can we adopt to express
the same theme / idea, I wonder. 
I think I like my rose quote better! 