Shogatsu is also said to be a milepost for the trip to the other world (this is otherwise kadomatsu [a decoration for the new year made of pine branches, etc.] is a milestone for the trip to the other world) and both of the sayings have the following phrase as their latter half: it should be celebrated and should not be.
正月は冥土の旅の一里塚（門松は冥土の旅の一里塚ともいい、「めでたくもあり、めでたくもなし」と続く。