Quoted from Rdoyle1978:

There's a thread around here from a postal worker describing the nightmare that recent management changes cost the USPS. Everybody knows about the sorting machines I think, but what isn't as well understood is an across-the-board denial of overtime, which is commonplace all year, and especially the holidays. So local post offices are having the hardest time dealing with the backlog, because they have the same level of staff as the rest of the year, PLUS things keep coming in.