What Was That Guy Thinking ?

We've all seen it before.  Season on the line.  One guy's hot, continually passing self-created and defensively imposed heat checks.  Shot clock's off.  The team starts their offense, gets some movement going, and then THAT guy.  Not the guy who's hot.  Not the guy who hit the fadeaway 25 footer to get you into the OT.  Not the guy who hit two 3's to get into the second OT, but instead, yes, THAT guy.  That OTHER guy, takes the shot and...surprise, surprise...CLANG.  No basket.  You lose.  And the glares begin in earnest.  
This phenomenon is one of my favorite things about watching non-NBA basketball.  It's so interesting to me, so nonsensical, but yet it happens so very often.  So I ask, what in the world was THAT guy thinking ? 
For an example, look no further than tonight's NCAA tournament thriller between Xavier and Kansas State.  For the two OT periods we were watching a two on one basketball game with some other people running around the court.  Xavier's Jordan Crawford and Terrell Holloway, taking on Kansas State's Jacob Pullen.  Back and forth they went for ten minutes.  Bucket by Crawford or Holloway, leading to a bucket by Pullen, and repeat.  At the end of the 2nd OT, with Xavier in the exact same position they'd been in at the end of regulation and the first OT,  down three with the ball. 
At this point, yes, I understand that Dante Jackson is one of the best shooters in his conference, yes, I understand that he was shooting over 50% for the game at that point, but unfortunately this gets away from the important point here : he isn't the hot man.  He hasn't been involved in the offense in a very long time.  He's simply not the best or the second best option to take this shot.    Unfortunately, here he comes around a screen with 10 entire seconds left on the clock, relatively open, and pulls the J and...well, I've already explained what happens next. 
Personally, I don't understand what that guy was thinking.  You have 10 seconds left on the clock, you have two guys who have proven that the basket is the size of the Grand Canyon in their eyes right now, two guys who will have no one writing about how poor their decision was (regardless of how bad the shot may appear), and you choose to shoot the ball, likely because "you're a shooter" or some other weak argument like that.  Everyone else on the court has one role at this point in the game, get the hot man open and get him the ball.  Unfortunately, THAT guy continually fails at this, bringing me both amusement and confusion in the same moment.
So really...what was THAT guy thinking ?