A "dinar" for her thoughts...

Like many European cities, it's really difficult to find a parking space in downtown Belgrade, so I always take the bus across the river to the center. One-ride tickets cost 29 dinars (about 53 cents) if you buy them at a kiosk, but more if you buy them in the bus. Working people and students can buy monthly passes. In any case, I am continually fascinated by people's faces. I stared at this lady's pensive expression for nearly the whole ride, and she was so absorbed in her thoughts that she didn't notice my snapping her picture as I held my camera on my knees. What's she thinking of?