Latin familiaris means family, home. Hence the “familiarity”. The meaning of the word has changed over time. By the beginning of the XVIII century, in the Russian language the word acquires a negative connotation. The Latin root is losing its former meaning. Familiarity now means inappropriate, obsessive ease, swagger.
Everyone’s life is divided into that which is open to all, and that which remains behind closed doors, in the circle of family or close friends. A person entering an inner, close circle has the right to some liberties in communication. A loved one has the right to give you unsolicited advice, to point out certain shortcomings, for example, in clothing or appearance. Suppose a mother gives her young daughter advice on what kind of clothes are preferable in a given situation. Is it familiarity? In most cases, no. After all, a daughter can also help her mother with the choice of clothes, focusing on her taste.
But it’s one thing when a close friend or family member advises you to correct something in the way you dress, and it’s quite another when a stranger, slapping you on the shoulder, says something like: “Old man, this tie / jacket / sweater doesn’t suit you ". Is it familiarity? Undoubtedly.
The concept of what is familiar and what is not, with time, of course, changes, like the rules of decency, the family way. For example, now in most families, children do not call their parents “you,” which was completely natural a hundred years ago. If you retreat even further, you can find funny definitions of what is familiarity. This, for example, is described by Saltykov-Shchedrin, in “Poshekhonskaya antiquity”. Greeting, the young man gave the lady he was caring for his hand - this was described as "unacceptable familiarity."
But back to today. There are things that can be discussed by a company of unfamiliar people or colleagues - weather, politics, and so on. And it is obvious that there are topics that a normal person is unlikely to want to discuss publicly and is unlikely to tolerate someone else's intervention in these areas. It’s also customary in Russia that unfamiliar and unfamiliar people turn to each other on “you”, moving to a less formal “you”, getting to know each other better and gaining permission from the interlocutor.
A familiar person does not want to acknowledge the existence of these rules. He is cheeky and too easy to communicate. Moreover, sometimes it seems to him that his familiarity is that which is dictated by love and care. Not true.
He is, by and large, indifferent to both the interlocutor and his reactions. He really wants to voice his own, the only correct point of view, to introduce his own, only acceptable, rules for everyone. He is not at all embarrassed by putting the interlocutor in an uncomfortable position, asking too personal questions, giving unsolicited advice. Easily switching to “you” even when communicating with a person older than himself, not to mention peers, he does not erase the boundaries, but creates new problems in communication. After all, he also needs to answer, and the ease of "poking" is not acceptable to everyone.
Familiar man is simply badly brought up. Sometimes he is not hopeless and quite amenable to education. If he comprehends the boundaries of the acceptable and permissible, then he can make a fairly pleasant conversationalist.