No shame in that; Nolasco's a pretty good pitcher. But the Nationals were already beating Nolasco 4-0, so perhaps what Harper did next wasn't in the best of form ...
Busting one's bat in the fourth inning when you've got a four-run lead does seem a bit childish, but what made this worse is that there might have been some collateral damage. A piece of that shattered bat might have bounced up and struck the umpire, or Marlins catcher John Buck.
Which Harper must have realized, because the next time up, he did apologize to Buck. From Juan C. Rodriguez (via SunSentinel.com):
When Harper, 19, came up again in the sixth he apologized to Buck.
"I saw it hit and that’s why I kind of jumped away," Buck said. "He told me he was really sorry, it was terrible. I told him, ‘Don’t worry about it. I did the same thing, but when I was your age it was a metal bat and I was in high school.’ It’s a learning experience for him...
That's a solid, classy response from Buck.
The lesson here is simple. You want to get mad when you strike out, and bust up something? That's fine. But be a man, and bust that stupid baseball bat over your own knee. That'll show it.