I'm sorry your letters/cards/packages have not been delivered yet.

I had a friend who worked for the Post Office a couple years ago, and I was told by her, that the mail first goes thru machines that read the addresses optically. The system looks for very simple easy to read lettering. (It really prefers simple font machine printed addresses and it prefers the address in a certain position on the envelope. If the return address is lower on the envelope than it should be, the scanner thinks thats the mail-to address) It pushes thru what it recognizes and spits the others out for hand-sorting. During the holidays, when mail volume is higher, and during this economy of using fewer and fewer manual hands to do the work, the hand-sorting sometimes got backed up at least 2-3 weeks behind.

So for the past couple years, I hand write notes inside my cards, letters, even bill payments, but use computer created printed labels for the outside. And the preprinted return address labels. I've had much less mail delivered late. Some still is, but much less.