The most salient characteristic that Abu Bakr (may Allah be pleased with him) continued to maintain even after he became caliph was his humbleness.

If his camel's bridle would fall to the ground, he would descend to pick it up for himself. When this happened on one occasion, someone said to him, "Had you ordered us, we would have handed it to you." Abu Bakr (may Allah be pleased with him) responded: "The Messenger of Allah (peace & blessings of Allah be upon him) ordered us not to ask people for anything."

At-Taareekh Al-Islaamee by Mahmood Shaakir (pg. 8)