While waiting for the flight, a middle-aged guy was sitting in front me. I noticed he unbuttoned his clothes, slipped his left palm under his right armpit. Followed by a few quick rubbing, he withdrew his hand. Yaccchhhhkkkk…. A few long thin black threads shown on his palm, and he swept it down on the floor… what the heck! Puked!!! I covered my mouth and nose subconsciously. Oh no… he repeated one more time and sniffed it. OMG… I lost my appetite for the next hours.