One noise as an early morning commuter is to hear the person sitting next to you start to bite their nails. and then you know theill be at it the whole journey. its just jarring when you hear the snap as they bite through the hard part and then the horrible peeling sound as they havent fully bitten through it so start to pull it away instead, revealing nasty barely there fingernails. THey need to not bite their nails on the train! also about it is when their teeth clash together when it breaks through the nail its horrible.