Competent people still make mistakes, they are not omniscient nor omnipotent. Being competent means that you did everything that a rational person ought to have

Competent people still make mistakes, they are not omniscient nor omnipotent. Being competent means that you did everything that a rational person ought to have done in a situation, and you did those things effectively. A perfectly competent person can be given bad intelligence about where their target will be, or the bomb they're dropping could have a faulty guidance system. Even with no external factors, if something were so easy that there was no need for human judgement, it would have been automated already. It is possible to commit no mistakes and still lose. That is not a weakness. That is life.