One feature of the product I am working on is "high five"ing content. The icon for this action is a hand. Should the hand icon be of a right or left hand? With the thumb on the right or left?
Is it for giving a high five or receiving one? A high five is normally given with the right hand. So an icon to give one would show the back of the right hand. Thumb on the left.
An image showing someone giving you a high five would show the front of the right hand. Thumb on the right.
Display both the left and right hand. Double high five. Double high fives are more exciting and then there's no bias to the left or right hand.