Over time, the blades inside an electrical outlet become loose. While it is a nuisance to you, loose blades are also an extreme fire hazard. These free blades cause extra heat to generate, which may lead to a fire. If you notice your outlets are no longer keeping plugs in, replace them.
Although there is space to plug in four appliances, this does not mean it is always safe to do so. You could overload the socket.This could cause the plug in the wall socket to overheat and possibly cause a fire.
So don't be like Ralphie's dad, and be aware and be safe!