Can you clarify your question just a little and let us know which conflicts you are talking about?

Not to come off as crass, but are you talking about:

• The massive revolts by monarchist / constitutional monarchists (leading to a civil war) that the fledgling Soviet state faced in the immediate post-revolutionary period?

• The American, English, French, and Japanese interventionist forces who invaded the Soviet Union in anti-Communist actions in the immediate post-revolutionary period?

• Poland's invasion of the Soviet Union in the immediate post-revolutionary period?

I would be the first to agree that Soviet military actions in the mid-twentieth century, and post-war period are defined by a particular sort of expansionism - but not matter how anti-Soviet you are, you have to know that the Soviet Union did not "immediately decide to start another war in europe" - they were only dealing with the wars thrust upon them.