Russian Social Taboos
Language and Address: Don't use "you" carelessly. Always use "Вы" (formal) for teachers/elders. A friend once used "ты" (formal) for a professor and was immediately glared at and felt guilty. Young people can be casual with each other, but it's best to be reserved for first meetings. Avoid making compliments: Never say a girl is "fat." Compliment her with "good temperament" (Хорошо выглядишь). Once, I complimented a classmate on being "curvy and cute," and she immediately showed me a recipe... When refusing, be direct: "I'll think about it" = no. Russians dislike beating around the bush. If a landlord says "maybe not" when renting a room, it actually means "get lost."
Body Language: Gestures = Indecent. Making the OK sign can be misinterpreted as lewd. When ordering food, I wanted to indicate "okay," but the waitress was confused. Luckily, she was very kind and patiently explained the gesture to me. Now I just say "один пожалуйста" (please give me one). Gesture = sarcasm. The thumbs-up gesture in Russia is equivalent to giving the middle finger; never use it to compliment someone. Last time I gave a friend a thumbs-up at a bar, a stranger took it as a provocation, almost causing an international conflict. Gesture = wanting to fight. This gesture will be considered provocative. Last time I made this gesture to a friend when parting at a coffee shop to tell them to keep in touch, my friend was so scared they quickly explained the gesture to me.
Gift Giving: Don't give flowers randomly. Roses must be an odd number, 3 is enough. Last time I wanted to buy 4 roses for my professor, the florist quickly told me that an even number of flowers is unlucky. Don't try to be clever at the dinner table. Bringing Chinese baijiu will be frowned upon; ordinary red wine around 2000 rubles is fine. Once, I brought Erguotou (a type of Chinese liquor), and all the Russians took a sip and secretly poured it into their potted plants... When visiting, be polite. Take off your shoes and coat before entering; it's awkward to arrive empty-handed. A chocolate bar for around 500 rubles from the supermarket will suffice.
Russians are like frozen yogurt—hard on the outside, but sweet inside once you've cooked them. Just don't ask them "Aren't you cold?" in winter; you'll get a look like they're looking at you like you're an idiot, plus the classic reply: "It's spring in Moscow."