But I can't go to Spain without a passport. What part of travel freely do you not get?.
You absolutely CAN 'travel freely' to Spain, and to each of the countries within the EU. You have a RIGHT to do so - you need not apply for any other permissions, visa or similar, because that RIGHT is enshrined in the EU freedoms.
You carry your passport to identify yourself AS a citizen of an EU nation, and thus a holder of that RIGHT.
Please desist from trolling.