Not everyone is emotional, its probably a big part of why he was/is

a good three point shooter. We need that back.
Stone cold killer, I'll take it!
I think the King of "Lets not get too crazy about anything" was Tim Duncan. Maybe Gabe emulates that. I used to love it when a player used to make a nice play and act like "Look at Me, That was Totally Awesome", and then watch Duncan make a far greater play in a bigger moment and act like "Yeah, I can do that pretty much anytime I feel like it, so what's the big deal?".
Personally, I'm always a little more fearful of a guy who pulls off amazing stuff and acts like "I'm just cruising. Wait until you see what I'll do to you if you actually get me fired up!". It's like, "if he thinks that Jaw-Dropping play was just par for the course, I wonder what he's actually capable of? Better not test him.".
Maybe on that charge, Gabe was thinking "I made the defensive rotation I was supposed to make, got into the spot I was supposed to get into, what's the big deal about just executing my assignment the way I'm supposed to?". Not saying that's what was in his head, but who knows?
If Gabe keeps playing the best and most consistent defense on the team and continues to work on other ways to contribute to the offense if the 3 isn't falling (if you're wide open and it's in rhythm, you've GOT to take it) I'm absolutely fine with him staying on the floor and not smiling.