A person with such a chin...

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He may suffer from deficiencies in mental development and circulatory problems. The person is also considered quick-tempered.

Since the chin reflects a person's actions... a sagging chin means...

The person acts quickly, but his thoughts cannot keep up with his actions.

Like this person...

He always makes many mistakes out of sudden impulse... Since his thinking cannot keep up with his emotions, he is unlikely to have a fruitful love relationship.