I used to get this when I took the bus. Really irritating. Could be worse, though. I work next to a sniffer and he does it in a really exaggerated way and then eats his phlegm noisily. Worse, he seems to have a cold for four days out of every five. Plus he picks his nose and eats it while you're having a conversation with him. He eats his dandruff too.
At least he doesn't suck his teeth on the days when he hasn't got a cold.