I dunno, ever since about age 14 Ive had serious trouble with eye contact except in specific circumstances.
If Im talking to somebody I dont know very well, or simply sitting down in a public area, I find myself struggling to avoid it for fear of...well, angering somebody, or simply being noticed.
With people much older than me (most of the professors at my college, for example) I can easily maintain eye contact for two hours, taking occasional breaks for things like blinking and note taking of course.
If I HAVE to make eye contact, I immidiatly flush and break into a sweat, and despite all the reassurances in the world, I still feel like Im doing something wrong, unless its with a person I know and trust, or, as mentioned above, an older person.