If you are in a good humour, you feel cheerful and happy, and are pleasant to people. If you do something with good humour, you do it cheerfully and pleasantly.
My answer is same with so called "Standard answer". The only difference is simplify and traditional Chinese characters. It is a political discrimination. "我喜欢她的好幽默" 與正確答案相同, 只是我用傳統字體 (繁體字), 而所謂 "標準答案" 是用簡體字的差別而已