Take the Bite - YouTube
All puppies are individuals. Some puppies may be excited to meet new people and some may be shy and afraid. The same can be applied to parrots. Birds who are frequently kept inside without change are less likely to enjoy going out and exploring than birds who are accustomed to it.
It is imperative that you know your birds body language and watch them with strangers. Some birds will readily step up for anyone or enjoy interacting with them while other birds will bite the first person who reaches out to touch said pretty bird. Please, *do not* allow strangers to touch your birds tail feathers as most birds get highly offended when something they can't see touches them. Other birds may accept some people (men over women, people with long hair over short, those with facial hair rather than without, tone of voice, etc) but not others.
It's one thing if you get bit by a dog... but most people rarely care if they get bitten by a bird, unless the damage is serious. If you know your bird bites, or is uncomfortable with strangers, let them know! Even if your bird doesn't bite, make sure they are aware that birds *can* bite. A bird that may be comfortable with you and never bite you may bite the snot out of a stranger!
That's why it is important to watch body language - and better yet, don't ignore the bite! Ignoring the bite may tell the parrot not to tell you, physically, when they are about to bite and go straight for the bite!