For me personally eye contact is very difficult. I was painfully shy as a child. So much so that in public I spent most of the time hiding behind my parents. In school I sat in the back corner and I don't think I said a word in class until I was well into high school. I've made myself come out of that shell (mostly) but I still have a very difficult time maintaining eye contact and will often look for a few seconds and then look away. I know I'm doing it, but I can't overcome that one little piece completely.