I also have a great Chris Hemsworth story! I like to think he's one of those celebrities who really is as nice as he seems.
A good friend of mine is a flight attendant, and last year had him on one of her flights. This airline has a lot of celebrities as customers and they have really strict rules about asking for pics and whatnot, but she said he was really friendly and carried on a conversation with all the flight attendants for the whole flight. After they landed he asked her if she wanted to take a pic with him and of course she said she did but it was against the rules. He proceeded to take a pic of them together with his phone and then texted it to her. Of course she would never bother him, but she couldn't resist saving his number in her phone. Her husband still jokes that she looks happier in that pic than she does in their wedding pics.