This is actually the best strategy, nothing that a good few gallons of beer can't solve  OP makes some really good points though, it's really important to take a step back at times and look at things from a holistic point of view, yes you could be much better off if you were god and you knew exactly what was going to happen, but you are not so you just have to do your best and if that leads to a profit then you can be very happy with that. This does not mean we should not be self critical and aim to learn and improve, it just means that it should stop short of chastising oneself.