Devon over at Black Pilled reviews Office Space - in and of itself a brilliant piece of propaganda, but one that tells several truths, instead of feeding poison pills of nihilism and pointlessness.
Now, I personally first stumbled into the concept of European (and descended) people being really, really nice, until suddenly, they're really, really not via Stefan Molyneux - and I don't think I've actually heard anyone describe it as a slow pressure cooker buildup. That said, I'm sure people do.
In my personal experience and observation, it really is a case of putting up with bullshit until it's not worth it anymore. It isn't passive aggressive - you do address the issue - but it's also about waiting to see if things resolve themselves, if the person giving you a ration of shit was just having a bad day, or realizes the error of his ways and makes amends.
But then you reach that moment where you just won't deal with it anymore. That straw that breaks the camel's back, taken in isolation, seems extreme, but at the moment that decision is made, the path taken will be very, very thorough, and seen as effective at getting rid of the problem, often being objectively effective as well.
I've seen someone decide to utterly stop talking to a family member, for months and years, because one day they just weren't willing to put up with covert abuse and manipulation for the sake of "family unity" any further, over a single comment. This comment, by itself, was bad enough, but as the endpoint in an ongoing pattern, was the final piece of a completed puzzle that said "it's not worth it", and "isn't ever going to stop being a manipulative, selfish cunt."
It's important to note, whether or not there is an explosion, that this isn't a pressure cooker building up. This is a point where the decision is made that whatever "this" is, is simply not worth dealing with anymore, and how do we make it go away?