When I have finished picking people up and dropping them off and doing another couple of hours helping the new high schoolers with their homework, I like to sit in the sun room in the dark. I forget about it till I'm turning off the lights to go to bed. Then I notice the Christmas lights that never made it down, making the room all glowy and blue.
It is rather still and special to sit alone in the peace of the late evening, looking at the mountain and faint glow of the city beyond . I should go to bed but then it seems I will wake up almost immediately and start again. So I forfeit some sleep for the luxury of doing nothing, being wanted by nobody and not having to be anywhere by a certain time... in the blue room.
PS It seems women who work have always had this problem as explained here so succinctly by the marvellous Madeleine Kahn.