What did the Russian expect? Since the beginning, it was known that their threat of cutting off gas supplies to Ukraine would have a negative effect on them too. First of all, putting the threat into practice was very difficult. 90% of the Russian gas directed to western Europe goes through Ukraine. What Ukrainians have to do in case of a blockade is to divert that gas by saying they have the right to do it.
Therefore, the only explanation is that the threat had not commercial purposes. It was a punishment of Ukraine for Víktor Yushchenko’s pro-western policy. That’s not a good policy for its only consequence is to weaken Russia’s image as a reliable supplier of gas, an industry where image is vital.
Even during the Soviet era, the USSR was seen as a reliable partner with regard to gas supplies. Russia’s transition to capitalism relieved Europe even more, an Europe that continued developing the use of gas for energy. The United Kingdom did the same thing and the British energy sector increased gas consumption from 1 or 2% in 1980 to 30% nowadays. Consequently, today London depends on Russia too. The gas coming from the Gulf could be used as substitute but it could also be missing. Fortunately, Norway is still discovering more gas reserves.

Source
Japan Times (Japan)
El más antiguo diario en lengua inglesa en el Japón, fundado en 1897.

Gas as a weapon of choice”, by David Howell, Japan Times, January 13, 2006.