The explanation that makes you look best may still be true; vanity alone does not disprove it.

Suspicion of your own motives can go too far. Just because an explanation happens to reflect well on you does not make it false, and reflexively discarding it is its own distortion, one that looks like humility. The test is the evidence, not whether the conclusion is comfortable.

When you catch yourself dismissing a flattering account, check it the way you would check any other. Ask what would be true if it were right. Rigorous self-doubt that only ever runs in one direction is not rigour.