1. A Hao's jealousy: When A Hao was in prison, he heard that Gangzi was doing well outside and was jealous. After he got out of prison, he settled accounts with Gangzi, perhaps to test Gangzi's strength, or perhaps to attack him out of jealousy.
2. Ah Hao's fault-finding behavior: Ah Hao may be finding fault with Gangzi, which is based on his praise in prison and his desire to vent his dissatisfaction and imbalance through the conflict with Gangzi.
The above reasons are for reference only. It is recommended to consult relevant people for more background information and real reasons.