People can lie looking into your eyes, and if you don't know very well the person body language, they will fooled you.
And yes, is more easy look at some other place when somebody is talking, i can hear and think about it better.
I can do eye contact when i know the person well enough, i dont like it, but i do.
Well, some days are better then the others.
I don't think it's a good thing stares at the eye ball of the other person while they are speaking, it feels kinda unnatural for me.
I remember look at my female teacher breasts when i was much more young, its very embarrassing to say this but its just that i wasn't comfortable looking their faces, so i look to the mouth and the eyes sight kinda slip without me knowing.
I have now a male teacher that have big green eyes and like very much to make eye contact with his students while in class. I can't look at him, no way.
If i have to look at the person's eye they faces kinda disappeared, i can't remember seeing they faces very well.
In general feels uncomfortable, it's like they are reading your mind.