Does anyone else seem to lose hours in the day?

It happens too often, where another day is at its end and I've gotten not much done and I'm left wondering where the day went. 

I think back to all the tasks I had done during the day, and roughly add them up, like X for 1 hour, Y for 2 hours, Z for 30 mins etc... even rounding them up considerably, and including general "fartassing around time" to help try explain it, but I still always fall short of the total hours of the day and am left with several hours of missing day unaccounted for.