When other people fail, we tend to think there’s something wrong with them. We say they’re lazy, stupid or feckless (of course, we don’t think that when *we* fail).
In reality, people’s behaviour is a product of their ability and the circumstances. Take the superb developer who manages her first project and crashes it burning into the ground. Or the mild mannered tester who morphs into the micro-managing boss from hell as soon as he starts running a team. Or the super-star designer who starts delivering ill-thought out, impractical and impossible to implement product designs. Or the support engineer who aced his interview but who can’t actually do the work of helping customers solve their problems*.
When that happens, it’s tempting to write the person off: to say that Alice will never run a project that again, that she simply doesn’t have it in her; that Bob is inherently incapable of running a team; that Charles is too flakey to rely on; that David isn’t good enough.
But people fail often not because of some soul-deep, inalterable essence, but because they lack the skills they need to succeed, or because they’re in a situation that sucks. Alice didn’t have a mentor; Bob is too scared to delegate; the project Charles is on has been set up to fail; nobody is giving David direction.
One possibility is that the person is genetically incapable, or has some deep character flaw that renders them useless. If that is true then their behaviour will be consistent across a broad set of different circumstances. But if they are succeeding one minute, and then failing the next, open your mind to other explanations.
* I made these up.