Tuhaf al-'Uqul: "He who begins his day thinking of something other than God is not one of the people of God. He who does not care for the affairs of the believers is not one of them. He who succumbs to humility is not with us; the Prophet’s family."

وقال صلى الله عليه وآله: من أصبح من أمتي وهمته غير الله فليس من الله. ومن لم يهتم بأمور المؤمنين فليس منهم. ومن أقر بالذل طائعا فليس منا أهل البيت

It means someone who willingly agrees to be humiliated or disgraced, for instance, those who sold themselves out to tyrants such as Yazid in exchange for money or material benefits, even though they knew it was wrong. 

Humbleness, in the sense of not being egotistical or arrogant, is a good quality ethically.

However, it is also good to have a balance - it is good to be humble as long as people are respectful, but if they start stepping on you or taking advantage of you, then it is good to assert yourself politely.

Of course, a believer is always humble towards Allah.