Agreed.
I used rescuetime, or maybe some competitor, for a few weeks.
I spend 60 hrs in the office, and am far more disciplined than I ever have been before in my life...and it was hard to clock 45 hrs of REAL work.
Depressing.
On the other hand, better to do that AND HAVE DATA than to do it and not know the truth.
Data lets you create a feedback loop and improve.