If they do, it could be because they want to feel more like part of the family, or it's just a particular animal's personality and that animal was matched with the person meant for it.
The golden I used to have did similar things w/her ears/eyes when I approached w/a leash. It was a habit formed from years of me sliding a new collar on with the leash attached. She'd squint and pull her ears back in anticipation of the collar being slid over her head.
The smile? I never got that.
If it's commercially made chocolate, they'd have to eat a lot to get sick. If it's 'real' chocolate, a little amount can be sufficient to really make them sick. Commercial chocolate is a lot of fake stuff.
That is a happy ending! My SIL's boxer ran out the door one Christmas morning at the other SIL's house. We all watched in horror as she dashed into the street and ran INTO an car. She bounced off the passenger door, and seemed completely unphased!
