When Abu Bakr (ra) was caliph, after salat al-fajr he would go out into the desert. Umar (ra) was curious where he went so decided to follow him. He saw Abu Bakr (ra) travel and come to a tent. He went in for a while before making his way back to the Medina.
Umar (ra) went into the tent and found an old women there with children. He asked her about her situation; she told him that "I am an old ageing widow who is raising orphan children and I am blind."
Umar (ra) then asked her about the man who visited her. She said "I have no idea about his name or who he is. He comes everyday and he cooks the food, kneads the dough, bakes the bread, cleans the tent/house, cleans the clothes, milks the goat and then leaves." Umar (ra) asked if she paid him anything to which she replied, "I have no money." Umar (ra) asked how long he has been doing this and she replied, "a long time."
Umar (ra) then left the women and commented, "You have made it a difficult job for the caliphs after you Abu Bakr!"