Is it stupid to go to a university which is ranked around 160 by Times Higher Education for a Master's degree? You should consider additional information. First, I recommend deciding what you want to do after getting your master's degree. Then consider if the degree program you are applying for will help you achieve that goal. If you are not sure, check the program or school website for statistics, or contact the program's alumni for advice.
Since this is the academia stack exchange, let's assume for the moment you want to continue in academia. In this case, the university's reputation (which is correlated with its ranking) is very important, but the specific program's reputation is even more important. (edit: People who know little about you will judge you based on the institution/program where you got your degree, because it is easy for them.) Working with a well-known faculty member can also have great importance.
Certainly rankings will not inform you if you will like living or working at an institution. Finally, normally each time you change institutions the prestige of your new position will decrease.