Germany made a decision to become dependent on Russian natural gas, piped in via the NordStream pipelines. Their Green Party insisted on a reduction in burning coal and running nuclear reactors to generate electricity, and the German government caved.
One presumes the Germans reasoned that Russia would become as dependent on German euros as Germany was on Russian gas. Given a healthy market economy and representative government in both countries, that might have proven to be the case.
However, the Russian economy isn't exactly a market economy, beset as it is by oligarchs. And Putin isn't a freely elected official, chosen in a competitive marketplace of candidates and ideas. Putin is more-or-less "president for life" and at his behest, the Russian army attacked Ukraine. With NATO, Germany has supported Ukraine.
Echoing the motto of the Starks from Game of Thrones: Winter is coming. Germany is worrying about Russia cutting off their gas supply. With a shortage of gas, or maybe a shutoff, things will get uncomfortable and maybe even dangerous for Germans.
Once again Germany will live with the consequences of its unfortunate choices. Former Chancellor Angela Merkel was a particularly unfortunate choice who pursued many wrong-headed policies, not just reliance on Russian gas.