Knowing they're at their intended destination and you can't go get them. 
We moved (like this weekend) and my new dipes are at our old address just waiting to be picked up and DH has the van at work...
BFP #1 10/28/09 EDD 06/24/10- Miscarriage 11/2/09
BFP #2 11/30/09 EDD 08/12/10- Sophia Grace born 8/1/10
BFP #3 11/16/10 EDD 08/04/11- Samuel Richard born 7/28/11
BFP #4 01/04/12 EDD 09/19/12- Simon Nathaniel born 9/6/12
BFP #5 03/27/13 EDD 11/25/13- Savannah Lee born 11/18/13
Re: Know what's worse than waiting for fluffy mail?
DS Born: 6/02/2012
Tied the Knot: 11/14/2015
Trying for Number Two since 9/1/15
BFP!!! Baby 2 Due: 12/6/21