Out of control kids, parents who just don't a give a **** about their child, feet on the seats, onboard flytippers who seeming enjoy abandoning their crap behind (where's their manky teeth and stolen untaxed Ford Transit) I'd make these people purchase a £3 travel cup so that they can enjoy their cup of tax avoiding crap without them leaving the place looking like a pigsty, onboard trolley - just get rid of the catering. No catering - less rubbish, people who don't know how to lock the toilet door, idiots who try to ram their pushbike on a peak hour service, those in suits, rude passengers... I could go on.
On one occation a youngish woman was having a go at a disabled passenger for sitting opposite her. I turned round and said ' if he wants to sit there let him, I'm not putting up with someone yelling and bawling over someone sat opposite them - get a grip.' One thing I did notice what that she did shut up.
Only the other day I had to put up with one wild child using me and two other passengers as climbing appararus prior to him jumping up and down on the table in front of me making loud noises whist the mother had nipped to the bog, I complained to the mother who said that he is expressing himself.