Mac's Grub Shak in in Spring Hill, Tennessee, doesn't have the fanciest menu. So big tips are far and few between. A few days ago, a man sat at down at Claire Hudson's table and ordered two beers and a spicy burger to accompany his special Coney Island Dog. He ate, he paid, he left. When Claire went to bus the table, she was stunned to find he'd left her a $36 tip. But it wasn't until she flipped the receipt over and saw this note that she burst into tears.