Perhaps it is simply down to the fact that the average train contains an accurate representative sample of both men and women from all walks of life. And whilst the polite, courteous, law abiding citizens fade comfortably into the background, happy to immerse themselves in their books or mobiles, the others are very much THERE. In your face. Often literally. Making you resent the very shared air that you breathe.
Although these people come in all shapes and sizes, they fall into six very distinct categories:
1) Loud people. Who actually talks/laughs that loud in everyday life? And incidentally, why do they always have an accent (usually Northern)? Do these people wander into the office each day and shout directly into the faces of their work colleagues? In their defence, they're usually happy. Again in their defence, any voice sounds louder on a train. But they really need to learn voice control.
2) Youths. The girls are ruder than we used to be. The boys really need to pull their trousers up a notch. Both the girls and the boys really need to get a room or at least learn to kiss with their mouths shut. Especially at 7am in the morning.
3) Arrogant men. You know the ones. They are immediately recognisable by how far apart their legs are. And they absolutely, categorically refuse to move over when you sit down, resulting in you perching side saddle in the seat you have paid good money to occupy, trying not to touch them for fear they'll take it as a come-on (which they will).
4) Women beautifying themselves. I'm not talking about simply putting on a bit of mascara. I'm talking full blown facial make-over. One girl once gassed me with nail varnish remover. Another plucked her in-growing leg hairs and flicked the hairs onto my lap. What most people do in the privacy of their bathrooms, others do on trains.
5) The ill. They never have a tissue. They cough like they're about to dislodge a small toad from their throats. They never put their hands in front of their mouths. And they will happily sneeze on you and not feel ashamed.
6) The pissed. I leave them until last because they are without a doubt, the most irritating passengers on trains. They shout. They start fights. If you're really unlucky they will vomit on your shoes (or worse). And do you know what makes it worse? They may fall under this category at 11pm on the train home, but you can guarantee they were in categories 1 to 5 above on the way out.
You might even recognise the girl who filed her nails on you.