Why it works?

Often times a remote doesn’t work because the batteries aren’t making good contact. They may have shifted, be poorly made, or there may be corrosion. Slapping the remote in these cases may move the batteries enough to make better contact or dislocate corrosion. As to why it is intuitive to slap a remote- chalk it up to primitive natures. Hitting machines that don’t work is both a trope of fiction as well as a common behavior of many people. When frustrated we often hit things.