When you look into the mirror and see a pimple staring you right back, that sudden moment can give you an urge to squeeze it. And after picking at a zit, you feel satisfied too. And when pimples come at worst times, it feels the best to pop them out manually.
Regardless of the reason, you need to understand that popping a pimple manually can damage your skin. Watch this nasty video that relates how to pop a pimple properly.