be contrary
悖 centers on going against what is expected or correct: being contrary, rebellious, or inconsistent with reason or order.
悖 combines 忄 (heart/mind) with 孛, which likely contributes the sound and carries a sense of disorder or rebellion. The exact historical development of 孛 is uncertain.
The heart radical 忄 beside 孛 suggests a mind that rebels or goes against the norm. Picture a contrary heart that always does the opposite of what is expected.
For ハイ, imagine a rebellious person shouting 'Hi!' (ハイ) in a formal setting where a bow is expected, acting contrary to proper etiquette.