Want to see what swines have refused your friends requests on Facebook? It's really easy to do it. 4 steps, 5 seconds ...
Click on the Friends Icon on your Facebook page, upper right hand corner.
Click on 'See All' at the bottom of the list.
In the top left hand corner of the dialogue box that pops up you'll see an option 'No New Friends Requests' unless you currently have some pending. Below that, you'll see another option called 'View Sent Requests'
Click on that, and you'll see a listing of everyone that you've sent requests to who haven't responded. You now have a nice list of people that you don't need to worry about sending Xmas cards to!