From the youngest level of sports, you learn to shake the other team's hand after the game. Generally it's just a slap and a bunch of unenthusiastic "googame googame googame" repeated as you walk in a line past each other, but it's the thought that counts.
Steven Adams of the Thunder wanted to shake Byron Mullens' hand at the end of the Thunder's big win over the Clippers, but Mullens apparently does not think it's the thought that counts.
So Adams had to shake his own hand.
It's not like Mullens doesn't notice. He looks down at Adams' hand, looks up, and keeps on moving, forcing the rookie to do the job himself.
Ahh, the old auto-celebration -- you know, shaking off. When nobody else will give you love, so you have to give yourself some. (That came out wrong.) Made famous by Andrew Bogut:
Adams is a Kiwi, and Bogut's an Aussie, so maybe people do this in the Southern Hemisphere? I don't know.