Often people who don't mesh were "invited to the party" because nobody fully realized the extent to which they're incapable of holding normal conversations without turning into passive-aggressive, condescending, neurotic, or permanently-negative messes.

Ultimately, there's only ever one common factor in all the failed interpersonal relationships in your life. Refuse to acknowledge that at your own peril.

E: Wait, 2021? Who even resurrected this. Why have you tricked me.