Of course, serious circumstances arise which excuse a person from attending Mass, such as if a person is sick, has to deal with an emergency, or cannot find a Mass to attend without real burden. A pastor may also dispense a person from the obligation of attending Mass for serious reason. For instance, no one, including our Lord, expects a person to attend Mass who is so sick he can not physically attend Mass; there is no virtue in further hurting one's own health plus infecting everyone else in the Church. Or, in the case of a blizzard, a person must prudently judge whether he can safely travel to attend Mass without seriously risking his own life and the lives of the others.