Can any one say that they know their minds?

I always think that I know my own mind, but then it goes and plays dirty tricks on me. For example. I want to lose weight. That's quite a common aspiration here amongst both men and women. You can do it the hard way, go to the gym, lift weights, run for miles, call an ambulance! Or the expensive way. Go once a week to a club where you are publicly weighed and then humiliated if you've gained or lost weight! My favourite though is to just use restraint. So why is it that I go to the kitchen to eat a low fat yoghurt and end up with a half litre of full fat ice cream instead?!! It's a crazy world in my mind.