In fact - almost all Polish history is dominated by the pressure from the stronger western neighbour.
anyhow the conclusion is - for almost 1000 years Poles had nothing but trouble with Germans!
The above are examples of the Polish chauvinist version of history.
The fact is that Poland was itself an aggressive, expansionist power for much of its history. As late as 1920 it was trying to conquer huge amounts of territory to the east.
For example, under King Boleslaw I ( reg. 1034-55), Poland conquered Lusatia, Moravia, Slovakia, northern Hungary, and part of the western Russian lands.
It was only in the 18th century that Poland decayed and became an object of aggression by its neighbours (not only to the west).
And the fact is that many Polish kings invited Germans to come and settle on their territories, for the purpose of developing their lands using the superior economic and technical skills of the German settlers. So much for nothing but trouble.
It is true that the English word "slave" and the corresponding German word "Sklave" are derived from the ethnic denominator "Slav".
But the reason for the etymological development has nothing to do with the Germans.
Before the Slavic tribes became christianised, Jewish merchants from Spain travelled to Slavic territories in Eastern Europe to buy slaves there for export to Spain and other Muslim lands. The reason why they bought slaves from the Slavs was that Church Law prohibited Jews from owning Christian slaves, but did not prohibit their owning slaves who were pagan, as the Slavs then were.
As a result, slaves of Slavic origin became very numerous in Muslim Spain, and eventually the Arabic word for "Slav", "Saqlabah", cameto be used to denote slaves in general, even those not of Slavic origin. That usage was then borrowed by the European peoples, beginning with the Spanish Christians, then by the French and Italians, finally spreading to the Germans and English, displacing the original Latin term "servus".
Medieval Germans did not use a derivative of "Slav" to describe the peoples to their east, but only the term "Wenden".