The retirement system is completely broken over here. As an employee you have to pay into it. I pay > 500€/mo, which a big part of my pay check and one of my largest expenses. My employer has to pay the same amount on top. You might or might not consider this essentially an additional cost for me as well. It is intended to be the primary pension plan for most people, though by the time I will go into retirement, the whole system will be unviable financially and I might get nothing. If I do get something, I get it starting after completing my 67th year of life. Of course I'd rather invest that money privately. If I choose to go into retirement early, I will have to pay hefty life-long penalties - 0.3% per month that I retire early. Obviously a couple of percent over 20 years of retirement or so can hurt quite a bit.
It might sound silly, but it's one of the main reasons I want to leave this country.