Hey!
1) cabs in Egypt...for the most part they just stress me out (even though they are essential to getting around)...although the worst cab was Fes, Morocco, where our driver hit a cyclist...luckily everyone was ok, but I must admit, I was a bit shaken up!
2) getting mistaken for a prostitute in Italy...I arrived in a small town near my dad's village and was waiting for the bus and apparently a girl wearing a dress with a duffel bag naturally equates to prostitute...needless to say, I learned my lesson!
3) The train from Belgrade to Bar (in Montenegro)...the distance was only about 200 km, but it took about 12 hours, because we had to stop for hours at a time on the track waiting for other trains to get buy...good times

On the whole though, I usually quite enjoy my international transportation, barring the occasional experience of getting locked in a bus's bathroom or tarvelling as a lone women and having 5 big strong men in the compartment (although that ended up quite well, they were all really nice!)
Cheers