Ian Happ put his head down and sprinted to third on a flyout that he mistakenly thought was a triple

Desire is a powerful thing, and a fierce motivator. 
So when Cubs rookie Ian Happ found himself a triple shy of the cycle in Wednesday's 17-3 win over the Pirates at Wrigley Field, he had one thing on his mind: hit a triple. In the sixth inning, he laced a drive to deep left field and the race was on. Problem was, he hadn't actually hit a triple. He hadn't actually hit a single, either, as the fly ball was caught by Starling Marte in the left-field corner.
Happ didn't know that, though. So he ran around the bases, coasting into third with what he thought was a cycle-securing three-bagger:

Oops! In the clip atop this post, notice how the crowd at Wrigley sounds audibly confused by the sequence, which is admittedly rather unusual.
Happ came up again two innings later but failed to record a triple, having to settle for an otherwise stellar 3-for-5 night with two runs scored and four RBIs.
"I loved the faux triple down the left field line -- that was outstanding," Maddon told MLB.com's Carrie Muskat after the game. "Good for him."
And Happ's take: "I hit it, I was hopeful, I got it pretty good, 355 down the line. It's a little deep. I didn't know if it was going to get to the wall. Guys get confused with the bricks sometimes. Marte tracked it down pretty easily. I didn't see it. I had my head down. I looked at the umpire and he signaled fair and I kept going. I hit it and turned on the after burners, but for no reason."
Happ had even more to say about his eventful evening in a postgame chat that aired on the broadcast:

We've all been there. We all experience this sort of sensation in one way or another, believing something is one way when it most certainly isn't. The difference, of course, is our individual lessons in this don't happen in front of tens of thousands of strangers -- hopefully.