Signs that the guy sitting next to you on the plane / train / bus / carriage / mule / elephant / etc. is going to ruin your trip:
1) he sits down and kicks off his shoes
2) he gets on a very loud cell phone call where he advises his friend to cheat on his wife, and offers to bail the friend out of jail if needed
3) he puts on his headphones and starts bouncing in his seat, enjoying the music.
4) ...then he starts playing air guitar and air drums
5) then he sneezes into his hand, rubs his hands together, and goes back to typing on his laptop
I think I need an upgrade...