I found that especially in London - people want to hurt you. However they need an excuse... here's an example that happened to me and my brother that is exactly what you're looking for OP:
Several years ago I was a bit drunk, it was midnight at Leicester Sq tube station, some of my mates were getting charged twice for their "all day railcard" because midnight had passed and they had to buy a new one even though the tube closed in 20 minutes.
I was talking to a friend a few meters away from the barriers, she told me what was happening, I said "oh, that's a bit shit"
The TFL staff member on the barrier managed to hear me say this and started screaming that I had verbally abused her. I was nowhere near her.
Another male TFL staff member then appeared and began screaming in my face, shouting and backing me down, saying I was verbally abusing staff.
I then started telling them to both fuck off and get out of my face.
These TFL staff did not think I had verbally abused them. They had, however, probably been enduring casual abuse from commuters all fucking day and wanted to be victims in order to be aggressors - at my expense.
I was drunk and I shouldn't have reacted, but especially the behaviour of the male TFL employee was so appalling I kept answering his bullshit with just as many swear-words. This is exactly what they wanted.
I was told to leave the station. My wife told me to go grab my brother, who was still buying tickets, and find a different route home with him.
TFL staff had called the cops on me by now.
I found my bro, he had no idea what had been happening to me.
The cops arrived and acted exactly the same as the tube staff. They wanted to cause a problem, they wanted to beat me up and needed an excuse to do it. They did not act like police officers, they asked the kind of questions that were designed to get me in trouble, and I still have the (albeit silent) CCTV to prove it. However I had lived in London for many years and I knew that, since the police were now here putting cuffs on me, the best thing I should do was be as passive and compliant as possible and give them no reason to hurt me. So instead they hurt my brother.
My brother was so concerned by the police behaviour he refused to believe they were police (they were in plain clothes and did not show their badges to him) and didn't want to leave my side. Immediately the police shifted their behaviour towards my brother. Immediately three police officers beat the shit out of my brother, who has never even been in a fight before in his life.
The police officers were later found, in court, to have corroborated their stories that my brother assaulted them. For six months they withheld CCTV evidence. For six months my brother was faced with the prospect of a permanent criminal record, when he's studying a Master's in Civil Engineering and has his whole life ahead of him.
In short - a lot of people in London want to hurt you. Not all of them, but too many of them. I now live in Cornwall.