I think a lot of the complaining comes from high taxes, remembering the "good old times" and just from being German. Germans love to complain.
I left Germany for a few years and came back. There are very few other places I could imagine to live in. Maybe Norway, Canada or Switzerland. I hope Germany gets its things together, the recent uprise of xenophobia and social polarization is concerning. I grew up in a Germany where it didn't matter where you came from or what you looked like.
Germany has been shifting wealth from middle class and lower class to the rich for a long time now and is at the forefront of inequality increase in Europe. All the xenophobia and polarization is happening for a reason. The people are no longer happy with their lives here. It is a result of decades of bad politicians and policies, bad election results, and mismanagement of the whole country and immigration and integration policies. Getting out shit together will require a massive mindset change, that personally I don't really see coming. We can forget all the mainstream parties like CDU, SPD, Greens, AFD, Left. They won't and don't want to bring us out of this situation. What they will do is continue the course of retiree pleasing policies, to catch tons of votes, while the rest of the country continues to go to shit.
You mean the “good old times” where people didn’t have foreigners imposed on them against their will and it destroy their culture and communities, while bleating things claiming it’s democracy to have sprinters imposed on you against your well to your and your children’s detriment?
I, a German, went to Switzerland for vacation once. I talked to a Swiss guy about how I like Switzerland and all that. I told him how impressed I was with how organized everything is and how well everything works. The train system and public transport in general is wonderful compared to the one we have in Germany, for example. To my surprise, he said something along the line of "yeah well, it only looks like that from the outside".
Perhaps the tendency to complain is a necessity to achieve a high level of efficiency.