If you are a naturally shy person then prolonged eye-contact is something that you avoid, and is one of the longest lasting problems if you are trying to become more extrovert.

I would say from my experience that prolonged eye-contact is considered rude in the South-West of England, whilst the avoidance of eye-contact is seen as rude in the North.

Whether a person is considered as trust-worthy is not connected to eye-contact alone (although excessive or minimal eye-contact is a warning signal), but to other body language in association with it.