Most people on Facebook have probably gotten a friend request from someone they didn't want to accept, and many of them just left the request pending instead of outright rejecting it, maybe seeing it as the nicer thing to do. The thing is, they've all probably been on the other side of that too, having sent friend requests that were never accepted and they likely just forgot about. If you want to see what friend requests of yours were left hanging, there's an easy way to do it. Click on the friend icon at the top of your Facebook page and then select "Find Friends." A page will load with all the people waiting to become your friend, and at the top there will be a small "View Sent Requests" button. If you click on that, you'll see what requests you've sent that haven't been approved.