Well first off... my iguana Kiwi gives me kisses... or at least he used to, lol. Before he got all mean and aggressive hahaha. But I'm working on it. I used to just say "Gimme kiss" and pucker up my lips and he'd lick me (okay that doesn't sound right, but you get the picture... I hope).
My burmese python Shakira always sticks her head up and sniffs around until I pet her after I open the lid up. I'm sure it's probably just because she's looking for some food. But she always seems so excited to see me... and almost is always trying to find a way to escape. Everytime she does get out she just sits in the middle of the floor... just lays there... It's pretty funny.
My male boa Jabez, and black blood python Tabu get extremely nippy when they're hungry. They will bite and lash out at anything until they're fed and happily full, then they become total sweethearts again. Plus Tabu likes to sit in his water bowl a few times a week. Maybe just because he likes to soak and get his skin extra-hydrated.
Lastly, my savannah monitor Acco has to have a nice warm bath right after getting him out of his cage, or he becomes wild and unhandleable. After he gets all wrapped up a towel and dried off he can be a sweetie-pie... but to me only. To everyone else it's like "meeeeehhhhh!!!!" *chomp*. It's awesome! haha. He also just loves to grab his food, hold it there, wait til I'm not watching, then gulp it down. He hates to eat in front of anyone... it makes him uncomfortable. I've gotten him somewhat to the point where he'll just snatch it outta the cage and eat it there without worries.
I think all my herps have something cool about them, but those are the coolest and most noticeable out of all of them. It's so cool how each one has a personality of its own