A shoe. It has a tongue, a throat, eyes (or eyelets) and a sole. I used soul here or else it would have given the answer away, but this riddle works best when told rather than read. And as the joke goes, old shoes never die, they just lose their sole.
You have fifty quarters on the table in front of you. You are blindfolded and cannot discern whether a coin is heads up or tails up by feeling it. You are told that x coins are heads up, where 0 < x < 50. You are asked to separate the coins into two piles in such a way that the number of heads up coins in both piles is the same at the end. You may flip any coin over as many times as you want.
More precious than gold, but cannot be bought, Can never be sold, only earned if it’s sought, If it is broken it can still can be mended, At birth it can’t start nor by death is it ended.
Friendship. It is more precious than gold to have a genuine friend, and true friendship cannot be bought or sold, only earned. When a friendship is broken it can be fixed and infants aren’t able to make friends until they’re older, but death can’t end it. Love doesn’t work as an answer because a friendship requires two people to interact, while parents love their children as soon as they’re born.
Your teeth. You get baby teeth and adult teeth as part of the life package, but once you lose those you get to pay for dentures (or scare small children with your sunken face).
Enderman are normally passive, but they become hostile if a player looks directly at them. The Enderman will stare back until the player looks away, and then attack the player. A bucket of water is the best way to defeat an Enderman.