A personal day is determined by what you do with your day. Reading a book, lounging in front of the tv, going for a bike ride, painting my nails, coloring my hair, wearing comfortable clothes, anything that brings a little enjoyment. A personal day does not have to do with work. Wearing you PJ's when working, as I work from home, might make you feel alright. However, it makes me slow and more sleepy. Wearing jeans and a comfortable t-shirt help my speed and attention.