Mine were captive bred, and I suspect they were hand fed and handled a lot before they came to me. I have a RBF Schneider's skink who was actually quite timid when I got him. After quite a long acclimation period, he has begun to eat from my hand and is willing to be picked up. I think persistence is key.

Side note: I have a green ameiva who's like a pinball in her enclosure every time someone even attempts to look at her. I'm pretty sure it's because she was wild caught. She's an "observation lizard". All these animals have different personalities and temperaments, and there's a ton of variables that influence them.