My informant, a friend from Turkey, fed our group of friends some Turkish coffee in special, tiny mugs. She told us that when we were finished drinking our coffee, to hand the cup to her so she could read our coffee lines. She read the coffee grind/water sludge that stuck to the bottom of our cups and judged for us the luck/goodness of our immediate futures, or lack thereof. According to her, the more white lines there are (the mug was white on the bottom), the more happiness is ahead of you.
The informant learned this from her surroundings, just by growing up in the culture of Turkey. She enjoys sharing it because it is something unique to her culture.