I check the email with the tracking number. I go to the site to track. I see the delivery is GUARANTEED by 3:00 today, so I start stalking the postal carrier, only to have him come and go with no package for me. 
This happens all the time with packages that are sent to me and packages I send.
Why offer guaranteed delivery if you can't follow through? Just say, "We'll try to have it there by Thursday, but there are no guarantees."
It's as disappointing as opening a Christmas present you thought was a video game only to find out it's socks. Boo hiss.
I'm going to start choosing vendors based on who they use for shipping.

This happens all the time with packages that are sent to me and packages I send.
Why offer guaranteed delivery if you can't follow through? Just say, "We'll try to have it there by Thursday, but there are no guarantees."
It's as disappointing as opening a Christmas present you thought was a video game only to find out it's socks. Boo hiss.
I'm going to start choosing vendors based on who they use for shipping.