While I was walking in the park the other day, I saw a particularly attractive little dog, whose wiggling, tail wagging and walking toward me seemed like a clear indication of friendly intentions. I let him sniff my hand, and when we were officially friends, I went to pet him. Нет! his owner said. Не надо его гладить. Он не любит фамильярности (Don't pet him. He doesn't like overfamiliarity.)
Now that is one sophisticated little mutt.
Overfamiliarity isn't actually something I think about much, nor is it a word I use very often. But фамильярность is used a fair bit in Russian, and it represents behavior that is considered extremely gauche. But to avoid doing it, first you've got to know what it is.
You commit the social sin of фамильярность when you act as if you are better friends with someone than you really are. Knowing someone for a long time doesn't mean you can poke through their medicine cabinet or purse: Несмотря на дружескую многолетнюю близость, между ними не было никакой фамильярности (Despite their close friendship over many years, they weren't informal with each other.) Working with someone for years doesn't mean you can ask them if they've got a hangover or are getting a divorce: Она держалась с коллегами ровно, без фамильярности, на длинной дистанции (She was very even-handed with her colleagues, never informal, and kept them at arm's length.) But one person's intrusive friendliness is another person's sign of love: Это не фамильярность с его стороны, а приступ нежности (He's not taking liberties, he's being romantic.)
Фамильярность is the behavioral buddy of панибратство, a wonderful word that I like to use for the sheer pleasure of the sound of it. It's from Polish, panie bracie, which sources say means something like "mister brother." It usually means treating someone who is higher up on the social, age, status, work or other scale as if he or she were your equal. But it can also mean being overly open and friendly with your peers.
Панибратство isn't as intrusive as фамильярность. It doesn't mean you're asking your boss about her sex life. Панибратство is more being all chummy with someone who isn't your chum. It might not be totally negative: Простота в общении — здесь главное. Существует некоторое даже панибратство, когда продавцы воспринимают тебя как соседа, а значит, как своего. (Here the most important thing is to be straightforward in dealings with people. It's even all right to be buddy-buddy, when the saleswomen treat you like a neighbor, and that means you're one of their own.)
But most of the time панибратство isn't a good thing. It's not exactly that you don't know your place, because панибратство can be practiced with people at or even below your social status: Мы были друзьями, но наша дружба развивалась как отношения людей умных и серьезных. Панибратство исключалось (We were friends, but our friendship developed as a relationship of smart and serious people. We weren't chummy at all.)
But панибратство usually means breaking standard social norms, and this can get very old-school: Такого панибратства, как теперь, не было. И право, лучше было, больше чтили старших, было больше порядка в семействах. (People weren't living out of each other's pockets like they are today, and it really was better that way; people respected their elders and there was more discipline in families.)
So when in doubt, keep your distance.