I think people are afraid ,they are afraid to show their imperfections.
They build a facade , they hide ashamed in fear of rejection .
So when 2 people meet , they present of themselves what they think is acceptable by society's fake standards . But once those imperfections start to surface , it's all down hill from there , free fall and crash losing what they thought they were and what they've become .
So to match someone or to have 'some' things in 'common' doesn't necessarily mean it's a connection but then again you may ask what is a real connection , what does it feel like really and what's it all about.

Therefore I think true connection is found through our wounds not through our similarities , that's what really maintains it and in this Stanza/Verse of poetry that I found what really describes what I'm aiming to impart:

"One heart is not connected to another through harmony alone.
They are, instead, linked deeply through their wounds. Pain linked to pain, fragility to fragility. There is no silence without a cry of grief, no forgiveness without bloodshed, no acceptance without a passage through acute loss. That is what lies at the root of true harmony."
- Haruki Murakami
So it's okay to be vulnerable and open to people , accept yourself , find pride in your wounds and don't be cold like the rest of them.