Jalen Ramsey Goes Off On J.R. Smith, 'Get the Strap!'

NFL star Jalen Ramsey basically spoke for everyone Thursday night when J.R. Smith brain-farted at the end of the NBA Finals ... questioning how the hell Smith screwed up so badly!

With the game tied, Smith got a crucial rebound with just seconds left in the game -- and instead of taking a shot or passing it to LeBron -- he tried to run out the clock, forcing the game into OT.

And you know the rest of the story goes ...

Jalen Ramsey was so baffled by J.R.'s move, he went to Instagram and fired off a 50 Cent-style rant.