Here's a breakdown of why the proverb is effective:
* Hyenas have a strong, unpleasant odor: This is a widely known fact, and it's often associated with scavengers and decay.
* We can't smell ourselves: Our own smell gets "normalized" to us, making us unaware of how strong it might be to others.
* The proverb connects these two concepts: It implies that just like a hyena can't smell its own foul odor, people can be oblivious to their own negative qualities.
So, in essence, the proverb is a metaphor for how our own perception can be skewed and how we might fail to recognize our flaws.