Only two driving crossings that have been a stop of more than 2-3 minutes: UAE into Oman (you have to stop at each country's border patrol building, go in and show a bunch of paperwork at each), and Croatia into Slovenia, where the border guard was so flummoxed by the stack of passports we handed him--one US, one Singaporean, one Bulgarian--that he kept us sitting in the car for 25 minutes, with a line of presumably fuming drivers stretching ever longer behind us. Still, no hint of actual trouble or bribery requests anywhere.