This is the obscene gesture that cost the Celtics' Marcus Smart $15,000

The Boston Celtics have been one of the outstanding surprises this NBA season, using a group effort and pure execution to climb into the top half of the Eastern Conference and top ten overall in the league.

The young Celtics are also a fiery, emotional bunch, and they let it all hang out on the court. Unfortunately for guard Marcus Smart, a recent outburst of enthusiasm comes with a price tag.

Smart was fined $15,000 for making an obscene gesture to an official in Boston's 105-104 win against the New York Knicks on Friday, the NBA announced on Monday. The gesture came late in the third quarter with the Celtics trailing by two, after Smart was whistled for an offensive foul. And here's exactly what went down:

From the reverse angle, you can see just how disappointed the official is in Smart:

He didn't want to call the technical, Marcus. But you gave him no choice.