One of the many reasons I pay extra to travel First class is that it significantly reduces your chance of being near to 'undesirables', eg dunk party goers, singing football hooligans, uneducated delinquents often shouting out appallingly vile language, etc etc. The late night weekend services from Edinburgh to Glasgow are particularity bad, especially on the Bathgate line.
Yeah, sorry about that
I am a regular traveler on this line, but I'd say that Aberdeen services are much worse for undesirables, at all times of the day. They have two-and-a-half hours to get progressively more drunk, and a small number of people regularly make use of every minute of their journey to gradually increase their blood alcohol content.
I also find First class passengers tend to dress smarter, indeed if I am traveling in First I will make more of an effort to look smart than if I were traveling standard, not that it bothers me if First class passengers wear scruffy jeans etc.
I'm not dressing up to travel FC, ever. When I do travel FC, I'm probably less likely to be in formalwear. I only travel FC on significant distances (to London, to Aberdeen), so I'd rather be comfortable than dressed to the nines. If anyone wants to judge me, I don't care.