"One who serves cannot hoard his free time; he has to give up the idea of being the master of his day," the pontiff said in a homily in Saint Peter's Basilica to mark the Church's Jubilee of Deacons.
"It deeply troubles me when I see a timetable in a parish: 'From such a time to such a time'. And then? There is no open door, no priest, no deacon, no layperson to receive people. This is not good," he said.
He also stressed the importance of priests and deacons being mild-mannered, saying: "Never shout, never".
Deacons from around the world and their families convened in Rome this weekend to take part in special jubilee as part of Francis' Jubilee year which is dedicated to the theme of mercy.
In a shock move earlier this month, the Argentine pontiff said he would set up a commission to study the possibility of women entering the Catholic clergy as deacons, in a potentially historic move for the Church.