I've noticed when I feed my dragon live crickets or meal worms he seems to go into "special" mode. He'll run over to whatever living thing happens to have drawn his attention, cock his head a few times and eat it. Then he'll kind of curl his tail up like a scorpion and you can see his sides moving in and out like he's breathing deeply a few times (sort of like a tired jogger). Then it's on to the next living thing. He doesn't do this when he eats salad or dried insects.
Mine does the same thing as long as I've had him. They curl their tail when 'hunting' and the breathing is excitement. He also gobbles them down extremely fast, haha.
I love Ramen and not to fond of steak, always too much fat to cut out, sushi's better to me. The only time food changes my behavior is if I find onions in it, then I get irritated, but I don't pant and stick my butt in the air, stomping around the room.
Dang onions..."Why did you put onions in this?", I asked.
"For flavor", was the reply ,"but don't worry you can't taste them."
"Soooo wait, you added onions for flavor, and you can't taste them, sooooooooooooooo...what flavor did they add?" I questioned.
"Onion flavor", they said. "Soooo you added onions for an onion flavor that you can't taste... " I asked as I silently
I have a plastic clear cup that I dust my roaches in and bring them in the house to feed my Beardie... When he sees the cup he leaps off his branch and paces back and forth against the glass... When I take the top off the viv he jumps back up on his branch and sometimes leaps out of the viv and into the cup!!! He goes nuts for live food!!!! I think it's just animal instinct and the thrill of the hunt...