For me the easiest tell is the up front, unprompted, and unsolicited declaration of nonpoliticalness. When someone takes the time and expends the breath to announce how nonpolitical they are, what follows is almost always a rant about how everything/everyone else is too political these days, and that of course leads into something between status quo advocacy and outright reactionary/regressive sentiments for some fabled time before those wicked politics were visible to the nonpolitical ranter. 
People that are hostile to service workers. Some just want to take some ideological stand against tipping when the service worker doesn't really have a choice and needs those tips to survive in the current unjust system in a way where ideological purity gestures toward that service worker just look like being a greedy and sanctimonious asshole. The worst of such people will actually declare, shamelessly, that they believe that service workers don't deserve a living wage. The implications of that are 
worthy.
I may get shit for this, but I'll say it anyway: this hair and beard combo, seen on living people. 
I have yet to meet anyone in person with that look that wasn't a chud.
(If one of you is a comrade with that look, I am sorry in advance for the prejudice and if I ever meet you in person I will atone by buying you a drink or something.)
Portland cement and it’s consequences have been a disaster for the human race.
E: I do wanna push back on the “figured it out yesterday” part of the lime cement story though. Builders have known about lime for a long time but concrete is reenforced with steel nowadays. A lime/brine cement would eat through the steel reinforcement in a couple of decades and all those pretty modern cantilever things would fall over.
It wasn’t until recently that we had reinforced plastic rebar to use in the same type of constructions (refer to table 3h for revised tension ratings). That’s why the whole internet is lit up with articles about Roman concrete, because we finally have reinforcement materials to build more with it than a patio grill.
I've never heard of plastic rebar, that's super interesting. i googled it and got "fiber-reinforced plastic," is that what you're talking about?
https://en.wikipedia.org/wiki/Fibre-reinforced_plastic
Yeah all that glass filled polymer and carbon fiber is just those compounds held together with some kind of plastic.
Basalt rebar is the same idea as well.
Tbh a better use for oil than burning the stuff.