If Germany is like other European countries, it also helps that your taxes are "automatically paid" to the government, usually by having the employer take them out of your salary and paying them. It's not like in US where Americans feel every dollar going to the government when they do their taxes. Since they are paid automatically, the income taxes aren't even on people's minds, usually.
However, if Europeans had to do their own taxes for their salaries, I'm sure many more would be upset about high taxes.
Even if your tax is paid automatically you can still recover taxes but it is hard and the laws are confusing. In Germany a special profession with a state exam (Steuerberater) as well as special associations (Lohnsteuerhilfeverein) exist or have been created to help individuals. For self-employed or people interested in recovering part of their taxes using those services is almost unavoidable.
In the US they take money out of your paycheck too. The only difference is once a year we "settle up" for the previous calendar year. You pay more if you're short and get some back if you overpaid.
There must be a similar process in Germany for people who aren't 9-5 types.
Anyone on a W-2 does have their taxes taken out automatically. That's what the whole purpose of filling out a W-4 prior to starting employment. Many people overpay in taxes and end up getting a substantial refund at the beginning of each year. How do Americans feel every dollar going to the government in this case?
Federal and state taxes are automatically withheld in the USA. Filing a return is usually an attempt to get some refunded, or in my case, getting screwed even more and writing a check. You can even be lucky enough to pay estimated taxes every quarter.
However, if Europeans had to do their own taxes for their salaries, I'm sure many more would be upset about high taxes.