When I first started door knocking, I was taught to categorize the leads in three ways. 1) "G" (good) means you sold it. 2) "NG" (no good) means you pitched it but didn't sell it. 3) "NFG" (no 'effin good) means they were home but wouldn't let you pitch it. Talk about trashing leads, we would literally crumple them up and throw them in the back seat. Still do.