MEKAI Morning Coffee Mug. 11 ounce. Changing Color Mug For You And Your Friend. Ceramic Heat Sensitive Color Changing Coffee Mug. Novelty Heat Sensitive Mug With Funny Smile

I really liked the happy and sad look for the cup... but when I actually got it, the smile is very visible prior to pouring something into the cup (example in picture). I guess it would be be great for a very dark room but any decent amount of light would show the smile clearly.