So far I've been very lucky: the worst I've experienced in three years of consulting travel has been a few hours delay in the airport, some uneventful <1h delays on the tarmac, and surly customs/CATSA/TSA staff. I've travelled ~60k miles each year, give or take.

Of course, now that I've mentioned this the gods will curse me and I'll end up with some brilliant horror stories to share with the FT Boards this week :P