A spoonful of tar in a barrel of honey.
More Russian Proverbs:
It was smooth on paper, but we've forgotten about ravines.Russian
A cross-eyed Tsar, one-eyed ministers, blind subjects.
Russian
You need a sharp axe for a tough bough.
Russian
Take care of clothes since they are new, take care of your honor since you are young.
Russian
The wife is twice precious only; when led into the house, and when taken out.
Russian
A beaten one is worth two unbeaten ones.
Russian