Dog Behavior: Personality trait or puppy phase?

This sounds like a mix between the two. It's great to hear that your dog has attached to you, but I can understand it being frustrating at times. The best way to handle this is going to be to teach your dog the "stay" command. It will be slow going at first, since you are trying to get him to do something that is the exact opposite of what he wants to do, but it can be done and you will both be happier.