Heightening observations (not convinced by this one !)

He was wearing a dark knitted hat, covering his long, thin head, and hiding his incipient baldness. I couldn't see his tall body behind the window, but he had long fingers and appeared to be quite skinny. He was smiling, his grey eyes shining as if full of mischief, which was quite surprising for a man his age. He welcomed the customers with a warm voice, asking the old lady in front of me how he could be of any help.
As I waited for my turn, our eyes crossed. He recognized me and nodded, smiling. The lady was now putting her receipt in her purse, and wishing him a good day. I stepped up.