Why:
- You don't have the time and the energy to do so; the risk of getting depressed or apathetic in such situations is quite high (once you are depressed you have another problem you don't want and can deal with); so discipline is the most important thing; to stay disciplined you MUST stay positive, 100%; thinking about 'micro-failures' doesn't help your mood; and btw, every situation can be seen positive or negative, you remember when people say the glass is half-full?
- Maybe the OP didn't do anything wrong, how do you want to know? Maybe it was the financial situation of the company, or they changed the product strategy over night or, or, or...; he might never find out the real reason, so any time spent on such thoughts is wasted time he could use for new endeavors
- Maybe in a year he can think back and learn from failures; but you know what, he doesn't have to sit down, think and learn from potential failures now: I am pretty sure that when he faces similar situations in future where he did mistakes in the past, he will remember and will act accordingly and automatically without the need to prepare himself