My 4 year old son only accepts appreciation, he cannot accept "No,Don't..".
A few neighbor kids came home to play with my son, he slightly tapped a 2 year old friend in his head, a 12 year girl who saw it told me "aunt, your son is beating him". On hearing this my son got angry, went alone to the open terrace.
When he was playing with toys by building a tower, his 2 year-old friend pushed his tower over, then he threw a piece upon his friend. If his friend sits in his chair he pulls him in anger. If I am supporting his friends he shouts. Even in a crowd if any advice is given he shouts or sits down, removes his footwear.
I told him "If you beat or touch your friends, I will not allow them to play with you." He said no, I will not fight. Next time when his friend asks for the toy he has, he pulls him or throws the toy upon him and shouts.
He is a single child and whether that is the problem with sharing.