The highest tax rate in the Netherlands is 51,95% (Note that this only covers anything you make over ~70k+ a year, 0-20k is taxed ~35%, and 20-70 is taxed 40%). Then you pay 6-21% VAT over anything you buy, so yeah, in some scenarios you definitely lose >50% of your gross income to taxes.
https://www.belastingdienst.nl/wps/wcm/connect/bldcontentnl/...