When your teammate scores a goal, it's customary to run over to him and give him a celebratory hug as you revel in the joyous moment together. It is not customary, however, to slide tackle them in the face.
That didn't stop the antagonist of this clip from (accidentally) delivering a boot to his teammate's face mere seconds after he scored with a nice diving header in a Hong Kong FA Cup match between South China and Sun Hei. As his teammate's happiness instantly turned to mouth pain, his concern grew and he probably realized that sliding studs up towards his head wasn't the best idea.
And that's why everyone on South China now shouts "Stay away from me!!!" as soon as they score a goal.
Thanks to Ameer for the tip!