I know it's hard to relate to, and I am happy that you can't cause that would mean a great misfortune in your life. I meant situations like trusting the wrong person, exposing yourself by mistake, and -god forbid- being gullible, for however short a time. These are things that a rationalist, who expects a great deal of himself and tries so hard to be disciplined and wise, should it happen that he does them, it's very difficult to forgive himself.
Like imagine a situation that borders with tragedy, and it is caused by a stupid mistake (I don't mean like driving drunk, cause that is something that I can't relate to, I neither drink nor drive), like marrying an abusive person, losing a friend, bringing unhappiness into your life, all by one (or even worse) a couple of foolish mistakes. How can a rational mind move on from that, how can you forgive yourself, accept the reality of it, and most importantly overcome the shock of it! I know that thankfully many people never had to go through such an emotional and mental strain, but in my life, myself and family and friends have gone through that, so I am asking for input from someone who knows. Because, as it turns out, rationals are the most peculiar people on earth, we get post-traumatic stress when we make foolish mistakes.