Maybe it's a British thing, but we tend to be polite. Too polite.
Even if someone is inconsiderate, we apologize as though we did something wrong.
Prime offenders? People in supermarkets, specifically Costco.
They have nice wide isles and yet somehow, for some reason, some idiot will find a way to put their trolley sideways and keep a hand on it while reaching for something, thus blocking the entire isle.
Or another favorite ... you're going through the entrance and someone just stops, maybe to answer their phone.
How about you wait in a queue at a checkout for ages and when it's their turn, then they start looking for their purse.
How many times have you thought "idiot" or muttered under your breath?
I started using my outside voice, it's fucking awesome.
"wow, you managed to block the entire isle, good job!"
"here's an idea - move! Can you not walk and talk at the same time?"
"did you not think you were going to have to pay?"
You don't even have to talk - just crash into someone else's trolley and drive it out of the way or just push it down the isle. Stepping outside the social norm seems to leave people really puzzled.
It's my new favorite hobby. Maybe I'm just getting old, but it's really funny.