I just don't understand all that fuss with passports.
In Belgium, as in most European countries, you have to carry at all times an identification document, and show it on request from the competent authorities (most often the police). Even in your own country, in your home town. Also if you are asked to identify yourself at the bank, to get a registered mail at the post office, etc.
Most people have no passport, only an identity card (and it must be a valid one - in Belgium, the validity of an IC is five years, after which you have to go and get a new one).