Lets be open and speak our mind. maybe things could be worked out that way. who knows?

IMO mostly because we don't grow up in small communities, or try to date in small communities if we're online dating, where our mom knows their mom, our dad knows or does business with their dad, we've gone to school with each other our entire lives, all hung out at the dairy queen on saturday night because that's all there was, all sharing common community, belief, and behavioral bonds.

Most anyone of the opposite sex you will encounter anymore is a complete stranger.

Who else do you encounter every day, that are complete strangers, that want to talk to you, try to talk to you, try to be friendly, try to establish a rapport and relationship?
Salesman, advertising, people on t.v., telemarketers.
Fake people that want something from you.

So, you encounter a stranger, you have to get over the hurdle of immediately falling into a wary, danger, sense of "what do they want from me?" or "what do I want from them and what are they going to want in exchange?"

I think that would be a lot of the reason behind it being "very" difficult to relate with the opposite (sex?).

It's already "difficult" just because differences inherently influence a different style of communication.
I mean the Chinese, Africans, Venezuelans, they didn't establish English. They have their own language. They're different. Different locations, different lifestyles, different needs, different cultures.
Men and women are different. They have different communication.
Takes time to learn each others languages.
IMO that makes it "difficult" to relate.

Mix the two = "very difficult."