Some people feel uncomfortable when looking into other's people eyes, for instance people on the autism spectrum or with social anxiety.
If it's bothering you, that a certain person doesn't look you in your eyes, observe that person. Does it happen only with you or does the person avoid eye contact with other people too? I'd say, if the person avoids eye contact in general, then it's either a personal trait or habit or a cultural thing. If it's a woman, it could be that she's avoiding eye contact in order to not give you the impression that she's flirting.
As for me,it's hard to have an eye contact with a person during a talk and it doesn't mean that i don't respect this person or smth like that.It's just really uncomfortable for me(
It can be a matter of someone's personality!
I am an introvert and I rarely look people in the eye whilst talking to them, I mean important topics not just the usual pleasantries and small talk you might exchange at the beginning of a conversation. I just need to look away to collect and articulate my thoughts about the topic. But I always look them in the eye when I'm listening - provided they let me... :) I get along best with other introverts and usually they have to look away themselves when they are speaking... ;)
