Looking in people's eyes just makes me feel very worried and uncomfortable. I get a threatening vibe from people who make eye contact for more than a few seconds.
Avoiding prolonged eye contact is really *more natural*, if you think about it. In practically every single other species, staring into another's eyes isn't being open/friendly, it's a threat. Most animals hate it; if you look them straight in the eye, they'll soon look away.
A 'smile' isn't friendly among animals, either (including our extended family, the apes). It's just showing your teeth, which is another threat. Humans have got it all backwards.