Sometimes you think the customs agent is trying to steal your passport

After my Island hoping I headed to thessoliniki, Greece for a night before making my way north to Sofia, Bulgaria. Due to the economic crisis Greece has suspended all international trains so I instead had to take a bus. As we crossed the border an official of some sort got on the bus to check passports. Most people he just checked and then gave them back, but when he got to me he was holding the only other non-eu passport. After checking mine he kept it and then got off the bus. I was concerned, definitely, but as the bus wasn't moving I assumed I was just getting a stamp, however not being able to see my passport or the person that had it was not comforting. We waiting for about 5 minutes( 5 minutes will never seems as long as when you are imaging someone taking off with your passport) and then the bus started moving. I just about had a panic attack and ran to the front of the bus and began telling the bus driver that I didn't have my passport yet, and before I'd even gotten a whole word out he handed it back to me. I'm not quite sure what the rationale behind this process is, but I entered Bulgaria with my passport and a stamp. After we passed customs we stopped at the duty free shop where I bought a giant bag of m&ms to soothe my nerves