A traffic stop, a document check, a customs inspection, a hospital or a university admission. An official indicates that a problem can be resolved informally, or the person offers money to make a problem go away. In many countries this is an administrative matter or nothing at all. In Russia it is a criminal offence under Article 291, and the amount does not have to be large.
Amounts up to 10,000 roubles fall under Article 291.2, petty bribery, which carries up to a year. Above that, Article 291 applies, and the parts escalate with the sum: a significant bribe from 25,000 roubles, a large one from 150,000, an especially large one from 1,000,000. Giving a bribe for an unlawful act is a separate and heavier part regardless of the amount.