This might be just me, this excludes the pain afterwards.
In: Biology
To answer that properly, we first have to ask “how do we feel pain?”. It turns out that we have specialized nerve endings in our skin for feeling pain. They are imbedded vertically in the skin waiting to be stimulated by a cut or impact. When you stimulate one, you feel a tiny prick of pain. When you stimulate many, you feel a lot of pain. Now these receptors aren’t evenly distributed throughout the body. There are more on the hands and other sensitive areas, and fewer elsewhere. That’s why a papercut to the finger hurts more than one on your leg, for example. So, when you get a shot, it’s in an area with fewer pain receptors. Since the needle is small and moving in the same orientation as the nerve endings, it only activates a few pain receptors, or sometimes none at all. If they had to give the shot into the palm of your hand at an angle, you’d probably not bother getting the second shot unless you were REALLY motivated.
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