When my teammate and I started to get in to counting a lot, taking weekend trips and playing all the hours we could, camping out at places we knew we could get away with it... We both discussed having dreams of still counting cards at the table. It's funny - normally in dreams anything with numbers gets messed up (clocks, etc)... but in these 'counting' dreams I never dropped the count =P. It was mentally exhausting though, because instead of a good night of sleep I felt as though I'd been counting cards all night after doing it all day.