I've had a couple of scary experiences at an airport:

The first was in Gatwick where I'd just gone through the metal detectors and the police were conducting random sniffer-dog searches of people's bags just after. Anyway the police asked me to "stop, take off my bag, put it down and step away", I obliged and took a step back, the dog did it's sniffing on my bag, but then lept straight up at me. I was the scariest thing to happen to me in my life, I was so worried the police would think I had drugs on me (which I didn't). I suppose the dog didn't jump up in right way because nothing came of it, the police just apologised and let me go on my way, but it was bally scary.

The second happenned to me in Frankfurt airport after having visited my dad there. I was taking a DVD player back to the UK in my hand luggage, but German customs didn't particularly like it (even though I'm an EU resident travelling within the EU), they decided that they would send me over to some customs official who couldn't speak English and had to scan it with some special machine. It was all terribly confusing and time-consuming, and all over one little DVD player, oh well, that's life....